root/Source/core/html/HTMLMediaElement.cpp

DEFINITIONS

1. urlForLoggingMedia
2. boolString
3. documentToElementSetMap
4. addElementToDocumentMap
5. removeElementFromDocumentMap
6. canLoadURL
7. supportsType
8. setMediaStreamRegistry
9. isMediaStreamURL
10. m_audioSourceNode
11. didMoveToNewDocument
12. hasCustomFocusLogic
13. supportsFocus
14. isMouseFocusable
15. parseAttribute
16. finishParsingChildren
17. rendererIsNeeded
18. createRenderer
19. insertedInto
20. removedFrom
21. attach
22. didRecalcStyle
23. scheduleDelayedAction
24. scheduleNextSourceChild
25. scheduleEvent
26. scheduleEvent
27. loadTimerFired
28. error
29. setSrc
30. networkState
31. canPlayType
32. load
33. prepareForLoad
34. loadInternal
35. selectMediaResource
36. loadNextSourceChild
37. loadResource
38. setPlayerPreload
39. startDelayedLoad
40. loadType
41. trackIndexCompare
42. eventTimeCueCompare
43. updateActiveTextTrackCues
44. textTracksAreReady
45. textTrackReadyStateChanged
46. textTrackModeChanged
47. textTrackKindChanged
48. beginIgnoringTrackDisplayUpdateRequests
49. endIgnoringTrackDisplayUpdateRequests
50. textTrackAddCues
51. textTrackRemoveCues
52. textTrackAddCue
53. textTrackRemoveCue
54. isSafeToLoadURL
55. startProgressEventTimer
56. waitForSourceChange
57. noneSupported
58. mediaEngineError
59. cancelPendingEventsAndCallbacks
60. mediaPlayerNetworkStateChanged
61. mediaLoadingFailed
62. setNetworkState
63. changeNetworkStateFromLoadingToIdle
64. mediaPlayerReadyStateChanged
65. setReadyState
66. progressEventTimerFired
67. addPlayedRange
68. supportsSave
69. prepareToPlay
70. seek
71. finishSeek
72. readyState
73. hasAudio
74. seeking
75. refreshCachedTime
76. invalidateCachedTime
77. currentTime
78. setCurrentTime
79. duration
80. paused
81. defaultPlaybackRate
82. setDefaultPlaybackRate
83. playbackRate
84. setPlaybackRate
85. updatePlaybackRate
86. ended
87. autoplay
88. preload
89. setPreload
90. play
91. playInternal
92. pause
93. closeMediaSource
94. loop
95. setLoop
96. controls
97. setControls
98. volume
99. setVolume
100. muted
101. setMuted
102. startPlaybackProgressTimer
103. playbackProgressTimerFired
104. scheduleTimeupdateEvent
105. togglePlayStateWillPlay
106. togglePlayState
107. mediaPlayerDidAddTextTrack
108. mediaPlayerDidRemoveTextTrack
109. closeCaptionTracksChanged
110. addTextTrack
111. removeTextTrack
112. forgetResourceSpecificTracks
113. addTextTrack
114. textTracks
115. didAddTrackElement
116. didRemoveTrackElement
117. textTrackLanguageSelectionScore
118. textTrackSelectionScore
119. configureTextTrackGroup
120. configureTextTracks
121. havePotentialSourceChild
122. selectNextSourceChild
123. sourceWasAdded
124. sourceWasRemoved
125. mediaPlayerTimeChanged
126. mediaPlayerDurationChanged
127. durationChanged
128. mediaPlayerPlaybackStateChanged
129. mediaPlayerRequestFullscreen
130. mediaPlayerRequestSeek
131. mediaPlayerRepaint
132. mediaPlayerSizeChanged
133. buffered
134. played
135. seekable
136. potentiallyPlaying
137. couldPlayIfEnoughData
138. endedPlayback
139. stoppedDueToErrors
140. pausedForUserInteraction
141. updateVolume
142. playerVolume
143. updatePlayState
144. setPausedInternal
145. stopPeriodicTimers
146. userCancelledLoad
147. clearMediaPlayerAndAudioSourceProviderClient
148. clearMediaPlayer
149. stop
150. hasPendingActivity
151. contextDestroyed
152. isFullscreen
153. enterFullscreen
154. exitFullscreen
155. didBecomeFullscreenElement
156. willStopBeingFullscreenElement
157. platformLayer
158. hasClosedCaptions
159. closedCaptionsVisible
160. updateTextTrackDisplay
161. setClosedCaptionsVisible
162. webkitAudioDecodedByteCount
163. webkitVideoDecodedByteCount
164. isURLAttribute
165. setShouldDelayLoadEvent
166. mediaControls
167. hasMediaControls
168. createMediaControls
169. configureMediaControls
170. configureTextTrackDisplay
171. markCaptionAndSubtitleTracksAsUnconfigured
172. willRespondToMouseClickEvents
173. preDispatchEventHandler
174. defaultEventHandler
175. createMediaPlayer
176. setAudioSourceNode
177. audioSourceProvider
178. mediaGroup
179. setMediaGroup
180. controller
181. setController
182. setControllerInternal
183. updateMediaController
184. isBlocked
185. isBlockedOnMediaController
186. prepareMediaFragmentURI
187. applyMediaFragmentURI
188. corsMode
189. mediaPlayerSetWebLayer
190. mediaPlayerSetOpaque
191. mediaPlayerMediaSourceOpened
192. isInteractiveContent

/*
 * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "core/html/HTMLMediaElement.h"

#include <limits>
#include "HTMLNames.h"
#include "RuntimeEnabledFeatures.h"
#include "bindings/v8/ExceptionState.h"
#include "bindings/v8/ExceptionStatePlaceholder.h"
#include "bindings/v8/ScriptController.h"
#include "bindings/v8/ScriptEventListener.h"
#include "core/css/MediaList.h"
#include "core/dom/Attribute.h"
#include "core/dom/ExceptionCode.h"
#include "core/dom/FullscreenElementStack.h"
#include "core/dom/shadow/ShadowRoot.h"
#include "core/events/Event.h"
#include "core/frame/LocalFrame.h"
#include "core/frame/Settings.h"
#include "core/frame/UseCounter.h"
#include "core/frame/csp/ContentSecurityPolicy.h"
#include "core/html/HTMLMediaSource.h"
#include "core/html/HTMLSourceElement.h"
#include "core/html/HTMLTrackElement.h"
#include "core/html/MediaController.h"
#include "core/html/MediaError.h"
#include "core/html/MediaFragmentURIParser.h"
#include "core/html/TimeRanges.h"
#include "core/html/shadow/MediaControls.h"
#include "core/html/track/InbandTextTrack.h"
#include "core/html/track/TextTrackCueList.h"
#include "core/html/track/TextTrackList.h"
#include "core/loader/FrameLoader.h"
#include "core/rendering/RenderVideo.h"
#include "core/rendering/RenderView.h"
#include "core/rendering/compositing/RenderLayerCompositor.h"
#include "platform/ContentType.h"
#include "platform/Language.h"
#include "platform/Logging.h"
#include "platform/MIMETypeFromURL.h"
#include "platform/MIMETypeRegistry.h"
#include "platform/NotImplemented.h"
#include "platform/UserGestureIndicator.h"
#include "platform/graphics/GraphicsLayer.h"
#include "platform/weborigin/SecurityOrigin.h"
#include "public/platform/Platform.h"
#include "public/platform/WebContentDecryptionModule.h"
#include "public/platform/WebInbandTextTrack.h"
#include "wtf/CurrentTime.h"
#include "wtf/MathExtras.h"
#include "wtf/NonCopyingSort.h"
#include "wtf/Uint8Array.h"
#include "wtf/text/CString.h"

#if ENABLE(WEB_AUDIO)
#include "platform/audio/AudioSourceProvider.h"
#include "modules/webaudio/MediaElementAudioSourceNode.h"
#endif

using namespace std;
using blink::WebInbandTextTrack;
using blink::WebMediaPlayer;
using blink::WebMimeRegistry;

namespace WebCore {

#if !LOG_DISABLED
static String urlForLoggingMedia(const KURL& url)
{
    static const unsigned maximumURLLengthForLogging = 128;

    if (url.string().length() < maximumURLLengthForLogging)
        return url.string();
    return url.string().substring(0, maximumURLLengthForLogging) + "...";
}

static const char* boolString(bool val)
{
    return val ? "true" : "false";
}
#endif

#ifndef LOG_MEDIA_EVENTS
// Default to not logging events because so many are generated they can overwhelm the rest of
// the logging.
#define LOG_MEDIA_EVENTS 0
#endif

#ifndef LOG_CACHED_TIME_WARNINGS
// Default to not logging warnings about excessive drift in the cached media time because it adds a
// fair amount of overhead and logging.
#define LOG_CACHED_TIME_WARNINGS 0
#endif

// URL protocol used to signal that the media source API is being used.
static const char mediaSourceBlobProtocol[] = "blob";

using namespace HTMLNames;
using namespace std;

typedef HashMap<Document*, HashSet<HTMLMediaElement*> > DocumentElementSetMap;
static DocumentElementSetMap& documentToElementSetMap()
{
    DEFINE_STATIC_LOCAL(DocumentElementSetMap, map, ());
    return map;
}

static void addElementToDocumentMap(HTMLMediaElement* element, Document* document)
{
    DocumentElementSetMap& map = documentToElementSetMap();
    HashSet<HTMLMediaElement*> set = map.take(document);
    set.add(element);
    map.add(document, set);
}

static void removeElementFromDocumentMap(HTMLMediaElement* element, Document* document)
{
    DocumentElementSetMap& map = documentToElementSetMap();
    HashSet<HTMLMediaElement*> set = map.take(document);
    set.remove(element);
    if (!set.isEmpty())
        map.add(document, set);
}

class TrackDisplayUpdateScope {
public:
    TrackDisplayUpdateScope(HTMLMediaElement* mediaElement)
    {
        m_mediaElement = mediaElement;
        m_mediaElement->beginIgnoringTrackDisplayUpdateRequests();
    }
    ~TrackDisplayUpdateScope()
    {
        ASSERT(m_mediaElement);
        m_mediaElement->endIgnoringTrackDisplayUpdateRequests();
    }

private:
    HTMLMediaElement* m_mediaElement;
};

static bool canLoadURL(const KURL& url, const ContentType& contentType, const String& keySystem)
{
    DEFINE_STATIC_LOCAL(const String, codecs, ("codecs"));

    String contentMIMEType = contentType.type().lower();
    String contentTypeCodecs = contentType.parameter(codecs);

    // If the MIME type is missing or is not meaningful, try to figure it out from the URL.
    if (contentMIMEType.isEmpty() || contentMIMEType == "application/octet-stream" || contentMIMEType == "text/plain") {
        if (url.protocolIsData())
            contentMIMEType = mimeTypeFromDataURL(url.string());
    }

    // If no MIME type is specified, always attempt to load.
    if (contentMIMEType.isEmpty())
        return true;

    // 4.8.10.3 MIME types - In the absence of a specification to the contrary, the MIME type "application/octet-stream"
    // when used with parameters, e.g. "application/octet-stream;codecs=theora", is a type that the user agent knows
    // it cannot render.
    if (contentMIMEType != "application/octet-stream" || contentTypeCodecs.isEmpty()) {
        WebMimeRegistry::SupportsType supported = blink::Platform::current()->mimeRegistry()->supportsMediaMIMEType(contentMIMEType, contentTypeCodecs, keySystem.lower());
        return supported > WebMimeRegistry::IsNotSupported;
    }

    return false;
}

WebMimeRegistry::SupportsType HTMLMediaElement::supportsType(const ContentType& contentType, const String& keySystem)
{
    DEFINE_STATIC_LOCAL(const String, codecs, ("codecs"));

    if (!RuntimeEnabledFeatures::mediaEnabled())
        return WebMimeRegistry::IsNotSupported;

    String type = contentType.type().lower();
    // The codecs string is not lower-cased because MP4 values are case sensitive
    // per http://tools.ietf.org/html/rfc4281#page-7.
    String typeCodecs = contentType.parameter(codecs);
    String system = keySystem.lower();

    if (type.isEmpty())
        return WebMimeRegistry::IsNotSupported;

    // 4.8.10.3 MIME types - The canPlayType(type) method must return the empty string if type is a type that the
    // user agent knows it cannot render or is the type "application/octet-stream"
    if (type == "application/octet-stream")
        return WebMimeRegistry::IsNotSupported;

    return blink::Platform::current()->mimeRegistry()->supportsMediaMIMEType(type, typeCodecs, system);
}

URLRegistry* HTMLMediaElement::s_mediaStreamRegistry = 0;

void HTMLMediaElement::setMediaStreamRegistry(URLRegistry* registry)
{
    ASSERT(!s_mediaStreamRegistry);
    s_mediaStreamRegistry = registry;
}

bool HTMLMediaElement::isMediaStreamURL(const String& url)
{
    return s_mediaStreamRegistry ? s_mediaStreamRegistry->contains(url) : false;
}

HTMLMediaElement::HTMLMediaElement(const QualifiedName& tagName, Document& document)
    : HTMLElement(tagName, document)
    , ActiveDOMObject(&document)
    , m_loadTimer(this, &HTMLMediaElement::loadTimerFired)
    , m_progressEventTimer(this, &HTMLMediaElement::progressEventTimerFired)
    , m_playbackProgressTimer(this, &HTMLMediaElement::playbackProgressTimerFired)
    , m_playedTimeRanges()
    , m_asyncEventQueue(GenericEventQueue::create(this))
    , m_playbackRate(1.0f)
    , m_defaultPlaybackRate(1.0f)
    , m_networkState(NETWORK_EMPTY)
    , m_readyState(HAVE_NOTHING)
    , m_readyStateMaximum(HAVE_NOTHING)
    , m_volume(1.0f)
    , m_lastSeekTime(0)
    , m_previousProgressTime(numeric_limits<double>::max())
    , m_duration(numeric_limits<double>::quiet_NaN())
    , m_lastTimeUpdateEventWallTime(0)
    , m_lastTimeUpdateEventMovieTime(numeric_limits<double>::max())
    , m_loadState(WaitingForSource)
    , m_webLayer(0)
    , m_opaque(false)
    , m_preload(MediaPlayer::Auto)
    , m_displayMode(Unknown)
    , m_cachedTime(MediaPlayer::invalidTime())
    , m_cachedTimeWallClockUpdateTime(0)
    , m_minimumWallClockTimeToCacheMediaTime(0)
    , m_fragmentStartTime(MediaPlayer::invalidTime())
    , m_fragmentEndTime(MediaPlayer::invalidTime())
    , m_pendingActionFlags(0)
    , m_userGestureRequiredForPlay(false)
    , m_playing(false)
    , m_shouldDelayLoadEvent(false)
    , m_haveFiredLoadedData(false)
    , m_active(true)
    , m_autoplaying(true)
    , m_muted(false)
    , m_paused(true)
    , m_seeking(false)
    , m_sentStalledEvent(false)
    , m_sentEndEvent(false)
    , m_pausedInternal(false)
    , m_closedCaptionsVisible(false)
    , m_completelyLoaded(false)
    , m_havePreparedToPlay(false)
    , m_delayingLoadForPreloadNone(false)
    , m_tracksAreReady(true)
    , m_haveVisibleTextTrack(false)
    , m_processingPreferenceChange(false)
    , m_lastTextTrackUpdateTime(-1)
    , m_textTracks(nullptr)
    , m_ignoreTrackDisplayUpdate(0)
#if ENABLE(WEB_AUDIO)
    , m_audioSourceNode(0)
#endif
{
    ASSERT(RuntimeEnabledFeatures::mediaEnabled());

    WTF_LOG(Media, "HTMLMediaElement::HTMLMediaElement");
    ScriptWrappable::init(this);

    if (document.settings() && document.settings()->mediaPlaybackRequiresUserGesture())
        m_userGestureRequiredForPlay = true;

    // We must always have a ShadowRoot so children like <source> will not render
    // as they never have an insertion point.
    ensureUserAgentShadowRoot();
    setHasCustomStyleCallbacks();
    addElementToDocumentMap(this, &document);
}

HTMLMediaElement::~HTMLMediaElement()
{
    WTF_LOG(Media, "HTMLMediaElement::~HTMLMediaElement");

    m_asyncEventQueue->close();

    setShouldDelayLoadEvent(false);

    if (m_textTracks)
        m_textTracks->clearOwner();

    if (m_mediaController) {
        m_mediaController->removeMediaElement(this);
        m_mediaController = nullptr;
    }

    closeMediaSource();

    removeElementFromDocumentMap(this, &document());

    // Destroying the player may cause a resource load to be canceled,
    // which could result in userCancelledLoad() being called back.
    // Setting m_completelyLoaded ensures that such a call will not cause
    // us to dispatch an abort event, which would result in a crash.
    // See http://crbug.com/233654 for more details.
    m_completelyLoaded = true;

    // Destroying the player may cause a resource load to be canceled,
    // which could result in Document::dispatchWindowLoadEvent() being
    // called via ResourceFetch::didLoadResource() then
    // FrameLoader::loadDone(). To prevent load event dispatching during
    // object destruction, we use Document::incrementLoadEventDelayCount().
    // See http://crbug.com/275223 for more details.
    document().incrementLoadEventDelayCount();

    clearMediaPlayerAndAudioSourceProviderClient();

    document().decrementLoadEventDelayCount();
}

void HTMLMediaElement::didMoveToNewDocument(Document& oldDocument)
{
    WTF_LOG(Media, "HTMLMediaElement::didMoveToNewDocument");

    if (m_shouldDelayLoadEvent) {
        document().incrementLoadEventDelayCount();
        // Note: Keeping the load event delay count increment on oldDocument that was added
        // when m_shouldDelayLoadEvent was set so that destruction of m_player can not
        // cause load event dispatching in oldDocument.
    } else {
        // Incrementing the load event delay count so that destruction of m_player can not
        // cause load event dispatching in oldDocument.
        oldDocument.incrementLoadEventDelayCount();
    }

    removeElementFromDocumentMap(this, &oldDocument);
    addElementToDocumentMap(this, &document());

    // FIXME: This is a temporary fix to prevent this object from causing the
    // MediaPlayer to dereference LocalFrame and FrameLoader pointers from the
    // previous document. A proper fix would provide a mechanism to allow this
    // object to refresh the MediaPlayer's LocalFrame and FrameLoader references on
    // document changes so that playback can be resumed properly.
    userCancelledLoad();

    // Decrement the load event delay count on oldDocument now that m_player has been destroyed
    // and there is no risk of dispatching a load event from within the destructor.
    oldDocument.decrementLoadEventDelayCount();

    ActiveDOMObject::didMoveToNewExecutionContext(&document());
    HTMLElement::didMoveToNewDocument(oldDocument);
}

bool HTMLMediaElement::hasCustomFocusLogic() const
{
    return true;
}

bool HTMLMediaElement::supportsFocus() const
{
    if (ownerDocument()->isMediaDocument())
        return false;

    // If no controls specified, we should still be able to focus the element if it has tabIndex.
    return controls() || HTMLElement::supportsFocus();
}

bool HTMLMediaElement::isMouseFocusable() const
{
    return false;
}

void HTMLMediaElement::parseAttribute(const QualifiedName& name, const AtomicString& value)
{
    if (name == srcAttr) {
        // Trigger a reload, as long as the 'src' attribute is present.
        if (!value.isNull()) {
            clearMediaPlayer(LoadMediaResource);
            scheduleDelayedAction(LoadMediaResource);
        }
    } else if (name == controlsAttr) {
        configureMediaControls();
    } else if (name == preloadAttr) {
        if (equalIgnoringCase(value, "none"))
            m_preload = MediaPlayer::None;
        else if (equalIgnoringCase(value, "metadata"))
            m_preload = MediaPlayer::MetaData;
        else {
            // The spec does not define an "invalid value default" but "auto" is suggested as the
            // "missing value default", so use it for everything except "none" and "metadata"
            m_preload = MediaPlayer::Auto;
        }

        // The attribute must be ignored if the autoplay attribute is present
        if (!autoplay() && m_player)
            setPlayerPreload();

    } else if (name == mediagroupAttr) {
        setMediaGroup(value);
    } else {
        HTMLElement::parseAttribute(name, value);
    }
}

void HTMLMediaElement::finishParsingChildren()
{
    HTMLElement::finishParsingChildren();

    if (Traversal<HTMLTrackElement>::firstChild(*this))
        scheduleDelayedAction(LoadTextTrackResource);
}

bool HTMLMediaElement::rendererIsNeeded(const RenderStyle& style)
{
    return controls() ? HTMLElement::rendererIsNeeded(style) : false;
}

RenderObject* HTMLMediaElement::createRenderer(RenderStyle*)
{
    return new RenderMedia(this);
}

Node::InsertionNotificationRequest HTMLMediaElement::insertedInto(ContainerNode* insertionPoint)
{
    WTF_LOG(Media, "HTMLMediaElement::insertedInto");

    HTMLElement::insertedInto(insertionPoint);
    if (insertionPoint->inDocument()) {
        m_active = true;

        if (!getAttribute(srcAttr).isEmpty() && m_networkState == NETWORK_EMPTY)
            scheduleDelayedAction(LoadMediaResource);
    }

    configureMediaControls();
    return InsertionDone;
}

void HTMLMediaElement::removedFrom(ContainerNode* insertionPoint)
{
    WTF_LOG(Media, "HTMLMediaElement::removedFrom");

    m_active = false;
    if (insertionPoint->inDocument() && insertionPoint->document().isActive()) {
        configureMediaControls();
        if (m_networkState > NETWORK_EMPTY)
            pause();
    }

    HTMLElement::removedFrom(insertionPoint);
}

void HTMLMediaElement::attach(const AttachContext& context)
{
    HTMLElement::attach(context);

    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::didRecalcStyle(StyleRecalcChange)
{
    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::scheduleDelayedAction(DelayedActionType actionType)
{
    WTF_LOG(Media, "HTMLMediaElement::scheduleDelayedAction");

    if ((actionType & LoadMediaResource) && !(m_pendingActionFlags & LoadMediaResource)) {
        prepareForLoad();
        m_pendingActionFlags |= LoadMediaResource;
    }

    if (actionType & LoadTextTrackResource)
        m_pendingActionFlags |= LoadTextTrackResource;

    if (!m_loadTimer.isActive())
        m_loadTimer.startOneShot(0, FROM_HERE);
}

void HTMLMediaElement::scheduleNextSourceChild()
{
    // Schedule the timer to try the next <source> element WITHOUT resetting state ala prepareForLoad.
    m_pendingActionFlags |= LoadMediaResource;
    m_loadTimer.startOneShot(0, FROM_HERE);
}

void HTMLMediaElement::scheduleEvent(const AtomicString& eventName)
{
    scheduleEvent(Event::createCancelable(eventName));
}

void HTMLMediaElement::scheduleEvent(PassRefPtrWillBeRawPtr<Event> event)
{
#if LOG_MEDIA_EVENTS
    WTF_LOG(Media, "HTMLMediaElement::scheduleEvent - scheduling '%s'", event->type().ascii().data());
#endif
    m_asyncEventQueue->enqueueEvent(event);
}

void HTMLMediaElement::loadTimerFired(Timer<HTMLMediaElement>*)
{
    if (m_pendingActionFlags & LoadTextTrackResource)
        configureTextTracks();

    if (m_pendingActionFlags & LoadMediaResource) {
        if (m_loadState == LoadingFromSourceElement)
            loadNextSourceChild();
        else
            loadInternal();
    }

    m_pendingActionFlags = 0;
}

PassRefPtr<MediaError> HTMLMediaElement::error() const
{
    return m_error;
}

void HTMLMediaElement::setSrc(const AtomicString& url)
{
    setAttribute(srcAttr, url);
}

HTMLMediaElement::NetworkState HTMLMediaElement::networkState() const
{
    return m_networkState;
}

String HTMLMediaElement::canPlayType(const String& mimeType, const String& keySystem) const
{
    if (!keySystem.isNull())
        UseCounter::count(document(), UseCounter::CanPlayTypeKeySystem);

    WebMimeRegistry::SupportsType support = supportsType(ContentType(mimeType), keySystem);
    String canPlay;

    // 4.8.10.3
    switch (support)
    {
        case WebMimeRegistry::IsNotSupported:
            canPlay = emptyString();
            break;
        case WebMimeRegistry::MayBeSupported:
            canPlay = "maybe";
            break;
        case WebMimeRegistry::IsSupported:
            canPlay = "probably";
            break;
    }

    WTF_LOG(Media, "HTMLMediaElement::canPlayType(%s, %s) -> %s", mimeType.utf8().data(), keySystem.utf8().data(), canPlay.utf8().data());

    return canPlay;
}

void HTMLMediaElement::load()
{
    WTF_LOG(Media, "HTMLMediaElement::load()");

    if (UserGestureIndicator::processingUserGesture())
        m_userGestureRequiredForPlay = false;

    prepareForLoad();
    loadInternal();
    prepareToPlay();
}

void HTMLMediaElement::prepareForLoad()
{
    WTF_LOG(Media, "HTMLMediaElement::prepareForLoad");

    // Perform the cleanup required for the resource load algorithm to run.
    stopPeriodicTimers();
    m_loadTimer.stop();
    // FIXME: Figure out appropriate place to reset LoadTextTrackResource if necessary and set m_pendingActionFlags to 0 here.
    m_pendingActionFlags &= ~LoadMediaResource;
    m_sentEndEvent = false;
    m_sentStalledEvent = false;
    m_haveFiredLoadedData = false;
    m_completelyLoaded = false;
    m_havePreparedToPlay = false;
    m_displayMode = Unknown;

    // 1 - Abort any already-running instance of the resource selection algorithm for this element.
    m_loadState = WaitingForSource;
    m_currentSourceNode = nullptr;

    // 2 - If there are any tasks from the media element's media element event task source in
    // one of the task queues, then remove those tasks.
    cancelPendingEventsAndCallbacks();

    // 3 - If the media element's networkState is set to NETWORK_LOADING or NETWORK_IDLE, queue
    // a task to fire a simple event named abort at the media element.
    if (m_networkState == NETWORK_LOADING || m_networkState == NETWORK_IDLE)
        scheduleEvent(EventTypeNames::abort);

    closeMediaSource();

    createMediaPlayer();

    // 4 - If the media element's networkState is not set to NETWORK_EMPTY, then run these substeps
    if (m_networkState != NETWORK_EMPTY) {
        // 4.1 - Queue a task to fire a simple event named emptied at the media element.
        scheduleEvent(EventTypeNames::emptied);

        // 4.2 - If a fetching process is in progress for the media element, the user agent should stop it.
        m_networkState = NETWORK_EMPTY;

        // 4.3 - Forget the media element's media-resource-specific tracks.
        forgetResourceSpecificTracks();

        // 4.4 - If readyState is not set to HAVE_NOTHING, then set it to that state.
        m_readyState = HAVE_NOTHING;
        m_readyStateMaximum = HAVE_NOTHING;

        // 4.5 - If the paused attribute is false, then set it to true.
        m_paused = true;

        // 4.6 - If seeking is true, set it to false.
        m_seeking = false;

        // 4.7 - Set the current playback position to 0.
        //       Set the official playback position to 0.
        //       If this changed the official playback position, then queue a task to fire a simple event named timeupdate at the media element.
        // FIXME: Add support for firing this event.

        // 4.8 - Set the initial playback position to 0.
        // FIXME: Make this less subtle. The position only becomes 0 because of the createMediaPlayer() call
        // above.
        refreshCachedTime();
        invalidateCachedTime();

        // 4.9 - Set the timeline offset to Not-a-Number (NaN).
        // 4.10 - Update the duration attribute to Not-a-Number (NaN).


        updateMediaController();
        updateActiveTextTrackCues(0);
    }

    // 5 - Set the playbackRate attribute to the value of the defaultPlaybackRate attribute.
    setPlaybackRate(defaultPlaybackRate(), IGNORE_EXCEPTION);

    // 6 - Set the error attribute to null and the autoplaying flag to true.
    m_error = nullptr;
    m_autoplaying = true;

    // 7 - Invoke the media element's resource selection algorithm.

    // 8 - Note: Playback of any previously playing media resource for this element stops.

    // The resource selection algorithm
    // 1 - Set the networkState to NETWORK_NO_SOURCE
    m_networkState = NETWORK_NO_SOURCE;

    // 2 - Asynchronously await a stable state.

    m_playedTimeRanges = TimeRanges::create();

    // FIXME: Investigate whether these can be moved into m_networkState != NETWORK_EMPTY block above
    // so they are closer to the relevant spec steps.
    m_lastSeekTime = 0;
    m_duration = numeric_limits<double>::quiet_NaN();

    // The spec doesn't say to block the load event until we actually run the asynchronous section
    // algorithm, but do it now because we won't start that until after the timer fires and the
    // event may have already fired by then.
    setShouldDelayLoadEvent(true);

    configureMediaControls();
}

void HTMLMediaElement::loadInternal()
{
    // HTMLMediaElement::textTracksAreReady will need "... the text tracks whose mode was not in the
    // disabled state when the element's resource selection algorithm last started".
    m_textTracksWhenResourceSelectionBegan.clear();
    if (m_textTracks) {
        for (unsigned i = 0; i < m_textTracks->length(); ++i) {
            TextTrack* track = m_textTracks->item(i);
            if (track->mode() != TextTrack::disabledKeyword())
                m_textTracksWhenResourceSelectionBegan.append(track);
        }
    }

    selectMediaResource();
}

void HTMLMediaElement::selectMediaResource()
{
    WTF_LOG(Media, "HTMLMediaElement::selectMediaResource");

    enum Mode { attribute, children };

    // 3 - If the media element has a src attribute, then let mode be attribute.
    Mode mode = attribute;
    if (!fastHasAttribute(srcAttr)) {
        // Otherwise, if the media element does not have a src attribute but has a source
        // element child, then let mode be children and let candidate be the first such
        // source element child in tree order.
        if (HTMLSourceElement* element = Traversal<HTMLSourceElement>::firstChild(*this)) {
            mode = children;
            m_nextChildNodeToConsider = element;
            m_currentSourceNode = nullptr;
        } else {
            // Otherwise the media element has neither a src attribute nor a source element
            // child: set the networkState to NETWORK_EMPTY, and abort these steps; the
            // synchronous section ends.
            m_loadState = WaitingForSource;
            setShouldDelayLoadEvent(false);
            m_networkState = NETWORK_EMPTY;

            WTF_LOG(Media, "HTMLMediaElement::selectMediaResource, nothing to load");
            return;
        }
    }

    // 4 - Set the media element's delaying-the-load-event flag to true (this delays the load event),
    // and set its networkState to NETWORK_LOADING.
    setShouldDelayLoadEvent(true);
    m_networkState = NETWORK_LOADING;

    // 5 - Queue a task to fire a simple event named loadstart at the media element.
    scheduleEvent(EventTypeNames::loadstart);

    // 6 - If mode is attribute, then run these substeps
    if (mode == attribute) {
        m_loadState = LoadingFromSrcAttr;

        // If the src attribute's value is the empty string ... jump down to the failed step below
        KURL mediaURL = getNonEmptyURLAttribute(srcAttr);
        if (mediaURL.isEmpty()) {
            mediaLoadingFailed(MediaPlayer::FormatError);
            WTF_LOG(Media, "HTMLMediaElement::selectMediaResource, empty 'src'");
            return;
        }

        if (!isSafeToLoadURL(mediaURL, Complain)) {
            mediaLoadingFailed(MediaPlayer::FormatError);
            return;
        }

        // No type or key system information is available when the url comes
        // from the 'src' attribute so MediaPlayer
        // will have to pick a media engine based on the file extension.
        ContentType contentType((String()));
        loadResource(mediaURL, contentType, String());
        WTF_LOG(Media, "HTMLMediaElement::selectMediaResource, using 'src' attribute url");
        return;
    }

    // Otherwise, the source elements will be used
    loadNextSourceChild();
}

void HTMLMediaElement::loadNextSourceChild()
{
    ContentType contentType((String()));
    String keySystem;
    KURL mediaURL = selectNextSourceChild(&contentType, &keySystem, Complain);
    if (!mediaURL.isValid()) {
        waitForSourceChange();
        return;
    }

    // Recreate the media player for the new url
    createMediaPlayer();

    m_loadState = LoadingFromSourceElement;
    loadResource(mediaURL, contentType, keySystem);
}

void HTMLMediaElement::loadResource(const KURL& url, ContentType& contentType, const String& keySystem)
{
    ASSERT(isSafeToLoadURL(url, Complain));

    WTF_LOG(Media, "HTMLMediaElement::loadResource(%s, %s, %s)", urlForLoggingMedia(url).utf8().data(), contentType.raw().utf8().data(), keySystem.utf8().data());

    LocalFrame* frame = document().frame();
    if (!frame) {
        mediaLoadingFailed(MediaPlayer::FormatError);
        return;
    }

    // The resource fetch algorithm
    m_networkState = NETWORK_LOADING;

    // Set m_currentSrc *before* changing to the cache url, the fact that we are loading from the app
    // cache is an internal detail not exposed through the media element API.
    m_currentSrc = url;

    WTF_LOG(Media, "HTMLMediaElement::loadResource - m_currentSrc -> %s", urlForLoggingMedia(m_currentSrc).utf8().data());

    startProgressEventTimer();

    // Reset display mode to force a recalculation of what to show because we are resetting the player.
    setDisplayMode(Unknown);

    if (!autoplay())
        setPlayerPreload();

    if (fastHasAttribute(mutedAttr))
        m_muted = true;
    updateVolume();

    ASSERT(!m_mediaSource);

    bool attemptLoad = true;

    if (url.protocolIs(mediaSourceBlobProtocol)) {
        if (isMediaStreamURL(url.string())) {
            m_userGestureRequiredForPlay = false;
        } else {
            m_mediaSource = HTMLMediaSource::lookup(url.string());

            if (m_mediaSource) {
                if (!m_mediaSource->attachToElement(this)) {
                    // Forget our reference to the MediaSource, so we leave it alone
                    // while processing remainder of load failure.
                    m_mediaSource = nullptr;
                    attemptLoad = false;
                }
            }
        }
    }

    if (attemptLoad && canLoadURL(url, contentType, keySystem)) {
        ASSERT(!webMediaPlayer());

        if (m_preload == MediaPlayer::None) {
            m_delayingLoadForPreloadNone = true;
        } else {
            m_player->load(loadType(), m_currentSrc, corsMode());
        }
    } else {
        mediaLoadingFailed(MediaPlayer::FormatError);
    }

    // If there is no poster to display, allow the media engine to render video frames as soon as
    // they are available.
    updateDisplayState();

    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::setPlayerPreload()
{
    m_player->setPreload(m_preload);

    if (m_delayingLoadForPreloadNone && m_preload != MediaPlayer::None)
        startDelayedLoad();
}

void HTMLMediaElement::startDelayedLoad()
{
    ASSERT(m_delayingLoadForPreloadNone);

    m_delayingLoadForPreloadNone = false;

    m_player->load(loadType(), m_currentSrc, corsMode());
}

WebMediaPlayer::LoadType HTMLMediaElement::loadType() const
{
    if (m_mediaSource)
        return WebMediaPlayer::LoadTypeMediaSource;

    if (isMediaStreamURL(m_currentSrc.string()))
        return WebMediaPlayer::LoadTypeMediaStream;

    return WebMediaPlayer::LoadTypeURL;
}

static bool trackIndexCompare(TextTrack* a,
                              TextTrack* b)
{
    return a->trackIndex() - b->trackIndex() < 0;
}

static bool eventTimeCueCompare(const std::pair<double, TextTrackCue*>& a,
                                const std::pair<double, TextTrackCue*>& b)
{
    // 12 - Sort the tasks in events in ascending time order (tasks with earlier
    // times first).
    if (a.first != b.first)
        return a.first - b.first < 0;

    // If the cues belong to different text tracks, it doesn't make sense to
    // compare the two tracks by the relative cue order, so return the relative
    // track order.
    if (a.second->track() != b.second->track())
        return trackIndexCompare(a.second->track(), b.second->track());

    // 12 - Further sort tasks in events that have the same time by the
    // relative text track cue order of the text track cues associated
    // with these tasks.
    return a.second->cueIndex() - b.second->cueIndex() < 0;
}


void HTMLMediaElement::updateActiveTextTrackCues(double movieTime)
{
    // 4.8.10.8 Playing the media resource

    //  If the current playback position changes while the steps are running,
    //  then the user agent must wait for the steps to complete, and then must
    //  immediately rerun the steps.
    if (ignoreTrackDisplayUpdateRequests())
        return;

    // 1 - Let current cues be a list of cues, initialized to contain all the
    // cues of all the hidden, showing, or showing by default text tracks of the
    // media element (not the disabled ones) whose start times are less than or
    // equal to the current playback position and whose end times are greater
    // than the current playback position.
    CueList currentCues;

    // The user agent must synchronously unset [the text track cue active] flag
    // whenever ... the media element's readyState is changed back to HAVE_NOTHING.
    if (m_readyState != HAVE_NOTHING && m_player)
        currentCues = m_cueTree.allOverlaps(m_cueTree.createInterval(movieTime, movieTime));

    CueList previousCues;
    CueList missedCues;

    // 2 - Let other cues be a list of cues, initialized to contain all the cues
    // of hidden, showing, and showing by default text tracks of the media
    // element that are not present in current cues.
    previousCues = m_currentlyActiveCues;

    // 3 - Let last time be the current playback position at the time this
    // algorithm was last run for this media element, if this is not the first
    // time it has run.
    double lastTime = m_lastTextTrackUpdateTime;

    // 4 - If the current playback position has, since the last time this
    // algorithm was run, only changed through its usual monotonic increase
    // during normal playback, then let missed cues be the list of cues in other
    // cues whose start times are greater than or equal to last time and whose
    // end times are less than or equal to the current playback position.
    // Otherwise, let missed cues be an empty list.
    if (lastTime >= 0 && m_lastSeekTime < movieTime) {
        CueList potentiallySkippedCues =
            m_cueTree.allOverlaps(m_cueTree.createInterval(lastTime, movieTime));

        for (size_t i = 0; i < potentiallySkippedCues.size(); ++i) {
            double cueStartTime = potentiallySkippedCues[i].low();
            double cueEndTime = potentiallySkippedCues[i].high();

            // Consider cues that may have been missed since the last seek time.
            if (cueStartTime > max(m_lastSeekTime, lastTime) && cueEndTime < movieTime)
                missedCues.append(potentiallySkippedCues[i]);
        }
    }

    m_lastTextTrackUpdateTime = movieTime;

    // 5 - If the time was reached through the usual monotonic increase of the
    // current playback position during normal playback, and if the user agent
    // has not fired a timeupdate event at the element in the past 15 to 250ms
    // and is not still running event handlers for such an event, then the user
    // agent must queue a task to fire a simple event named timeupdate at the
    // element. (In the other cases, such as explicit seeks, relevant events get
    // fired as part of the overall process of changing the current playback
    // position.)
    if (!m_seeking && m_lastSeekTime <= lastTime)
        scheduleTimeupdateEvent(true);

    // Explicitly cache vector sizes, as their content is constant from here.
    size_t currentCuesSize = currentCues.size();
    size_t missedCuesSize = missedCues.size();
    size_t previousCuesSize = previousCues.size();

    // 6 - If all of the cues in current cues have their text track cue active
    // flag set, none of the cues in other cues have their text track cue active
    // flag set, and missed cues is empty, then abort these steps.
    bool activeSetChanged = missedCuesSize;

    for (size_t i = 0; !activeSetChanged && i < previousCuesSize; ++i)
        if (!currentCues.contains(previousCues[i]) && previousCues[i].data()->isActive())
            activeSetChanged = true;

    for (size_t i = 0; i < currentCuesSize; ++i) {
        currentCues[i].data()->updateDisplayTree(movieTime);

        if (!currentCues[i].data()->isActive())
            activeSetChanged = true;
    }

    if (!activeSetChanged)
        return;

    // 7 - If the time was reached through the usual monotonic increase of the
    // current playback position during normal playback, and there are cues in
    // other cues that have their text track cue pause-on-exi flag set and that
    // either have their text track cue active flag set or are also in missed
    // cues, then immediately pause the media element.
    for (size_t i = 0; !m_paused && i < previousCuesSize; ++i) {
        if (previousCues[i].data()->pauseOnExit()
            && previousCues[i].data()->isActive()
            && !currentCues.contains(previousCues[i]))
            pause();
    }

    for (size_t i = 0; !m_paused && i < missedCuesSize; ++i) {
        if (missedCues[i].data()->pauseOnExit())
            pause();
    }

    // 8 - Let events be a list of tasks, initially empty. Each task in this
    // list will be associated with a text track, a text track cue, and a time,
    // which are used to sort the list before the tasks are queued.
    Vector<std::pair<double, TextTrackCue*> > eventTasks;

    // 8 - Let affected tracks be a list of text tracks, initially empty.
    Vector<TextTrack*> affectedTracks;

    for (size_t i = 0; i < missedCuesSize; ++i) {
        // 9 - For each text track cue in missed cues, prepare an event named enter
        // for the TextTrackCue object with the text track cue start time.
        eventTasks.append(std::make_pair(missedCues[i].data()->startTime(),
                                         missedCues[i].data()));

        // 10 - For each text track [...] in missed cues, prepare an event
        // named exit for the TextTrackCue object with the  with the later of
        // the text track cue end time and the text track cue start time.

        // Note: An explicit task is added only if the cue is NOT a zero or
        // negative length cue. Otherwise, the need for an exit event is
        // checked when these tasks are actually queued below. This doesn't
        // affect sorting events before dispatch either, because the exit
        // event has the same time as the enter event.
        if (missedCues[i].data()->startTime() < missedCues[i].data()->endTime())
            eventTasks.append(std::make_pair(missedCues[i].data()->endTime(),
                                             missedCues[i].data()));
    }

    for (size_t i = 0; i < previousCuesSize; ++i) {
        // 10 - For each text track cue in other cues that has its text
        // track cue active flag set prepare an event named exit for the
        // TextTrackCue object with the text track cue end time.
        if (!currentCues.contains(previousCues[i]))
            eventTasks.append(std::make_pair(previousCues[i].data()->endTime(),
                                             previousCues[i].data()));
    }

    for (size_t i = 0; i < currentCuesSize; ++i) {
        // 11 - For each text track cue in current cues that does not have its
        // text track cue active flag set, prepare an event named enter for the
        // TextTrackCue object with the text track cue start time.
        if (!previousCues.contains(currentCues[i]))
            eventTasks.append(std::make_pair(currentCues[i].data()->startTime(),
                                             currentCues[i].data()));
    }

    // 12 - Sort the tasks in events in ascending time order (tasks with earlier
    // times first).
    nonCopyingSort(eventTasks.begin(), eventTasks.end(), eventTimeCueCompare);

    for (size_t i = 0; i < eventTasks.size(); ++i) {
        if (!affectedTracks.contains(eventTasks[i].second->track()))
            affectedTracks.append(eventTasks[i].second->track());

        // 13 - Queue each task in events, in list order.
        RefPtrWillBeRawPtr<Event> event = nullptr;

        // Each event in eventTasks may be either an enterEvent or an exitEvent,
        // depending on the time that is associated with the event. This
        // correctly identifies the type of the event, if the startTime is
        // less than the endTime in the cue.
        if (eventTasks[i].second->startTime() >= eventTasks[i].second->endTime()) {
            event = Event::create(EventTypeNames::enter);
            event->setTarget(eventTasks[i].second);
            m_asyncEventQueue->enqueueEvent(event.release());

            event = Event::create(EventTypeNames::exit);
            event->setTarget(eventTasks[i].second);
            m_asyncEventQueue->enqueueEvent(event.release());
        } else {
            if (eventTasks[i].first == eventTasks[i].second->startTime())
                event = Event::create(EventTypeNames::enter);
            else
                event = Event::create(EventTypeNames::exit);

            event->setTarget(eventTasks[i].second);
            m_asyncEventQueue->enqueueEvent(event.release());
        }
    }

    // 14 - Sort affected tracks in the same order as the text tracks appear in
    // the media element's list of text tracks, and remove duplicates.
    nonCopyingSort(affectedTracks.begin(), affectedTracks.end(), trackIndexCompare);

    // 15 - For each text track in affected tracks, in the list order, queue a
    // task to fire a simple event named cuechange at the TextTrack object, and, ...
    for (size_t i = 0; i < affectedTracks.size(); ++i) {
        RefPtrWillBeRawPtr<Event> event = Event::create(EventTypeNames::cuechange);
        event->setTarget(affectedTracks[i]);

        m_asyncEventQueue->enqueueEvent(event.release());

        // ... if the text track has a corresponding track element, to then fire a
        // simple event named cuechange at the track element as well.
        if (affectedTracks[i]->trackType() == TextTrack::TrackElement) {
            RefPtrWillBeRawPtr<Event> event = Event::create(EventTypeNames::cuechange);
            HTMLTrackElement* trackElement = static_cast<LoadableTextTrack*>(affectedTracks[i])->trackElement();
            ASSERT(trackElement);
            event->setTarget(trackElement);

            m_asyncEventQueue->enqueueEvent(event.release());
        }
    }

    // 16 - Set the text track cue active flag of all the cues in the current
    // cues, and unset the text track cue active flag of all the cues in the
    // other cues.
    for (size_t i = 0; i < currentCuesSize; ++i)
        currentCues[i].data()->setIsActive(true);

    for (size_t i = 0; i < previousCuesSize; ++i)
        if (!currentCues.contains(previousCues[i]))
            previousCues[i].data()->setIsActive(false);

    // Update the current active cues.
    m_currentlyActiveCues = currentCues;

    if (activeSetChanged)
        updateTextTrackDisplay();
}

bool HTMLMediaElement::textTracksAreReady() const
{
    // 4.8.10.12.1 Text track model
    // ...
    // The text tracks of a media element are ready if all the text tracks whose mode was not
    // in the disabled state when the element's resource selection algorithm last started now
    // have a text track readiness state of loaded or failed to load.
    for (unsigned i = 0; i < m_textTracksWhenResourceSelectionBegan.size(); ++i) {
        if (m_textTracksWhenResourceSelectionBegan[i]->readinessState() == TextTrack::Loading
            || m_textTracksWhenResourceSelectionBegan[i]->readinessState() == TextTrack::NotLoaded)
            return false;
    }

    return true;
}

void HTMLMediaElement::textTrackReadyStateChanged(TextTrack* track)
{
    if (m_player && m_textTracksWhenResourceSelectionBegan.contains(track)) {
        if (track->readinessState() != TextTrack::Loading)
            setReadyState(m_player->readyState());
    } else {
        // The track readiness state might have changed as a result of the user
        // clicking the captions button. In this case, a check whether all the
        // resources have failed loading should be done in order to hide the CC button.
        if (hasMediaControls() && track->readinessState() == TextTrack::FailedToLoad)
            mediaControls()->refreshClosedCaptionsButtonVisibility();
    }
}

void HTMLMediaElement::textTrackModeChanged(TextTrack* track)
{
    if (track->trackType() == TextTrack::TrackElement) {
        // 4.8.10.12.3 Sourcing out-of-band text tracks
        // ... when a text track corresponding to a track element is created with text track
        // mode set to disabled and subsequently changes its text track mode to hidden, showing,
        // or showing by default for the first time, the user agent must immediately and synchronously
        // run the following algorithm ...

        for (HTMLTrackElement* trackElement = Traversal<HTMLTrackElement>::firstChild(*this); trackElement; trackElement = Traversal<HTMLTrackElement>::nextSibling(*trackElement)) {
            if (trackElement->track() != track)
                continue;

            // Mark this track as "configured" so configureTextTracks won't change the mode again.
            track->setHasBeenConfigured(true);
            if (track->mode() != TextTrack::disabledKeyword()) {
                if (trackElement->readyState() == HTMLTrackElement::LOADED)
                    textTrackAddCues(track, track->cues());

                // If this is the first added track, create the list of text tracks.
                if (!m_textTracks)
                    m_textTracks = TextTrackList::create(this);
            }
            break;
        }
    } else if (track->trackType() == TextTrack::AddTrack && track->mode() != TextTrack::disabledKeyword()) {
        textTrackAddCues(track, track->cues());
    }

    configureTextTrackDisplay(AssumeVisibleChange);

    ASSERT(textTracks()->contains(track));
    textTracks()->scheduleChangeEvent();
}

void HTMLMediaElement::textTrackKindChanged(TextTrack* track)
{
    if (track->kind() != TextTrack::captionsKeyword() && track->kind() != TextTrack::subtitlesKeyword() && track->mode() == TextTrack::showingKeyword())
        track->setMode(TextTrack::hiddenKeyword());
}

void HTMLMediaElement::beginIgnoringTrackDisplayUpdateRequests()
{
    ++m_ignoreTrackDisplayUpdate;
}

void HTMLMediaElement::endIgnoringTrackDisplayUpdateRequests()
{
    ASSERT(m_ignoreTrackDisplayUpdate);
    --m_ignoreTrackDisplayUpdate;
    if (!m_ignoreTrackDisplayUpdate && m_active)
        updateActiveTextTrackCues(currentTime());
}

void HTMLMediaElement::textTrackAddCues(TextTrack* track, const TextTrackCueList* cues)
{
    WTF_LOG(Media, "HTMLMediaElement::textTrackAddCues");
    if (track->mode() == TextTrack::disabledKeyword())
        return;

    TrackDisplayUpdateScope scope(this);
    for (size_t i = 0; i < cues->length(); ++i)
        textTrackAddCue(cues->item(i)->track(), cues->item(i));
}

void HTMLMediaElement::textTrackRemoveCues(TextTrack*, const TextTrackCueList* cues)
{
    WTF_LOG(Media, "HTMLMediaElement::textTrackRemoveCues");

    TrackDisplayUpdateScope scope(this);
    for (size_t i = 0; i < cues->length(); ++i)
        textTrackRemoveCue(cues->item(i)->track(), cues->item(i));
}

void HTMLMediaElement::textTrackAddCue(TextTrack* track, PassRefPtr<TextTrackCue> cue)
{
    if (track->mode() == TextTrack::disabledKeyword())
        return;

    // Negative duration cues need be treated in the interval tree as
    // zero-length cues.
    double endTime = max(cue->startTime(), cue->endTime());

    CueInterval interval = m_cueTree.createInterval(cue->startTime(), endTime, cue.get());
    if (!m_cueTree.contains(interval))
        m_cueTree.add(interval);
    updateActiveTextTrackCues(currentTime());
}

void HTMLMediaElement::textTrackRemoveCue(TextTrack*, PassRefPtr<TextTrackCue> cue)
{
    // Negative duration cues need to be treated in the interval tree as
    // zero-length cues.
    double endTime = max(cue->startTime(), cue->endTime());

    CueInterval interval = m_cueTree.createInterval(cue->startTime(), endTime, cue.get());
    m_cueTree.remove(interval);

    // Since the cue will be removed from the media element and likely the
    // TextTrack might also be destructed, notifying the region of the cue
    // removal shouldn't be done.
    cue->notifyRegionWhenRemovingDisplayTree(false);

    size_t index = m_currentlyActiveCues.find(interval);
    if (index != kNotFound) {
        m_currentlyActiveCues.remove(index);
        cue->setIsActive(false);
    }
    cue->removeDisplayTree();
    updateActiveTextTrackCues(currentTime());

    cue->notifyRegionWhenRemovingDisplayTree(true);
}


bool HTMLMediaElement::isSafeToLoadURL(const KURL& url, InvalidURLAction actionIfInvalid)
{
    if (!url.isValid()) {
        WTF_LOG(Media, "HTMLMediaElement::isSafeToLoadURL(%s) -> FALSE because url is invalid", urlForLoggingMedia(url).utf8().data());
        return false;
    }

    LocalFrame* frame = document().frame();
    if (!frame || !document().securityOrigin()->canDisplay(url)) {
        if (actionIfInvalid == Complain)
            FrameLoader::reportLocalLoadFailed(frame, url.elidedString());
        WTF_LOG(Media, "HTMLMediaElement::isSafeToLoadURL(%s) -> FALSE rejected by SecurityOrigin", urlForLoggingMedia(url).utf8().data());
        return false;
    }

    if (!document().contentSecurityPolicy()->allowMediaFromSource(url)) {
        WTF_LOG(Media, "HTMLMediaElement::isSafeToLoadURL(%s) -> rejected by Content Security Policy", urlForLoggingMedia(url).utf8().data());
        return false;
    }

    return true;
}

void HTMLMediaElement::startProgressEventTimer()
{
    if (m_progressEventTimer.isActive())
        return;

    m_previousProgressTime = WTF::currentTime();
    // 350ms is not magic, it is in the spec!
    m_progressEventTimer.startRepeating(0.350, FROM_HERE);
}

void HTMLMediaElement::waitForSourceChange()
{
    WTF_LOG(Media, "HTMLMediaElement::waitForSourceChange");

    stopPeriodicTimers();
    m_loadState = WaitingForSource;

    // 6.17 - Waiting: Set the element's networkState attribute to the NETWORK_NO_SOURCE value
    m_networkState = NETWORK_NO_SOURCE;

    // 6.18 - Set the element's delaying-the-load-event flag to false. This stops delaying the load event.
    setShouldDelayLoadEvent(false);

    updateDisplayState();

    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::noneSupported()
{
    WTF_LOG(Media, "HTMLMediaElement::noneSupported");

    stopPeriodicTimers();
    m_loadState = WaitingForSource;
    m_currentSourceNode = nullptr;

    // 4.8.10.5
    // 6 - Reaching this step indicates that the media resource failed to load or that the given
    // URL could not be resolved. In one atomic operation, run the following steps:

    // 6.1 - Set the error attribute to a new MediaError object whose code attribute is set to
    // MEDIA_ERR_SRC_NOT_SUPPORTED.
    m_error = MediaError::create(MediaError::MEDIA_ERR_SRC_NOT_SUPPORTED);

    // 6.2 - Forget the media element's media-resource-specific text tracks.
    forgetResourceSpecificTracks();

    // 6.3 - Set the element's networkState attribute to the NETWORK_NO_SOURCE value.
    m_networkState = NETWORK_NO_SOURCE;

    // 7 - Queue a task to fire a simple event named error at the media element.
    scheduleEvent(EventTypeNames::error);

    closeMediaSource();

    // 8 - Set the element's delaying-the-load-event flag to false. This stops delaying the load event.
    setShouldDelayLoadEvent(false);

    // 9 - Abort these steps. Until the load() method is invoked or the src attribute is changed,
    // the element won't attempt to load another resource.

    updateDisplayState();

    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::mediaEngineError(PassRefPtr<MediaError> err)
{
    WTF_LOG(Media, "HTMLMediaElement::mediaEngineError(%d)", static_cast<int>(err->code()));

    // 1 - The user agent should cancel the fetching process.
    stopPeriodicTimers();
    m_loadState = WaitingForSource;

    // 2 - Set the error attribute to a new MediaError object whose code attribute is
    // set to MEDIA_ERR_NETWORK/MEDIA_ERR_DECODE.
    m_error = err;

    // 3 - Queue a task to fire a simple event named error at the media element.
    scheduleEvent(EventTypeNames::error);

    closeMediaSource();

    // 4 - Set the element's networkState attribute to the NETWORK_EMPTY value and queue a
    // task to fire a simple event called emptied at the element.
    m_networkState = NETWORK_EMPTY;
    scheduleEvent(EventTypeNames::emptied);

    // 5 - Set the element's delaying-the-load-event flag to false. This stops delaying the load event.
    setShouldDelayLoadEvent(false);

    // 6 - Abort the overall resource selection algorithm.
    m_currentSourceNode = nullptr;
}

void HTMLMediaElement::cancelPendingEventsAndCallbacks()
{
    WTF_LOG(Media, "HTMLMediaElement::cancelPendingEventsAndCallbacks");
    m_asyncEventQueue->cancelAllEvents();

    for (HTMLSourceElement* source = Traversal<HTMLSourceElement>::firstChild(*this); source; source = Traversal<HTMLSourceElement>::nextSibling(*source))
        source->cancelPendingErrorEvent();
}

void HTMLMediaElement::mediaPlayerNetworkStateChanged()
{
    setNetworkState(m_player->networkState());
}

void HTMLMediaElement::mediaLoadingFailed(MediaPlayer::NetworkState error)
{
    stopPeriodicTimers();

    // If we failed while trying to load a <source> element, the movie was never parsed, and there are more
    // <source> children, schedule the next one
    if (m_readyState < HAVE_METADATA && m_loadState == LoadingFromSourceElement) {

        // resource selection algorithm
        // Step 9.Otherwise.9 - Failed with elements: Queue a task, using the DOM manipulation task source, to fire a simple event named error at the candidate element.
        if (m_currentSourceNode)
            m_currentSourceNode->scheduleErrorEvent();
        else
            WTF_LOG(Media, "HTMLMediaElement::setNetworkState - error event not sent, <source> was removed");

        // 9.Otherwise.10 - Asynchronously await a stable state. The synchronous section consists of all the remaining steps of this algorithm until the algorithm says the synchronous section has ended.

        // 9.Otherwise.11 - Forget the media element's media-resource-specific tracks.
        forgetResourceSpecificTracks();

        if (havePotentialSourceChild()) {
            WTF_LOG(Media, "HTMLMediaElement::setNetworkState - scheduling next <source>");
            scheduleNextSourceChild();
        } else {
            WTF_LOG(Media, "HTMLMediaElement::setNetworkState - no more <source> elements, waiting");
            waitForSourceChange();
        }

        return;
    }

    if (error == MediaPlayer::NetworkError && m_readyState >= HAVE_METADATA)
        mediaEngineError(MediaError::create(MediaError::MEDIA_ERR_NETWORK));
    else if (error == MediaPlayer::DecodeError)
        mediaEngineError(MediaError::create(MediaError::MEDIA_ERR_DECODE));
    else if ((error == MediaPlayer::FormatError || error == MediaPlayer::NetworkError) && m_loadState == LoadingFromSrcAttr)
        noneSupported();

    updateDisplayState();
    if (hasMediaControls())
        mediaControls()->reset();
}

void HTMLMediaElement::setNetworkState(MediaPlayer::NetworkState state)
{
    WTF_LOG(Media, "HTMLMediaElement::setNetworkState(%d) - current state is %d", static_cast<int>(state), static_cast<int>(m_networkState));

    if (state == MediaPlayer::Empty) {
        // Just update the cached state and leave, we can't do anything.
        m_networkState = NETWORK_EMPTY;
        return;
    }

    if (state == MediaPlayer::FormatError || state == MediaPlayer::NetworkError || state == MediaPlayer::DecodeError) {
        mediaLoadingFailed(state);
        return;
    }

    if (state == MediaPlayer::Idle) {
        if (m_networkState > NETWORK_IDLE) {
            changeNetworkStateFromLoadingToIdle();
            setShouldDelayLoadEvent(false);
        } else {
            m_networkState = NETWORK_IDLE;
        }
    }

    if (state == MediaPlayer::Loading) {
        if (m_networkState < NETWORK_LOADING || m_networkState == NETWORK_NO_SOURCE)
            startProgressEventTimer();
        m_networkState = NETWORK_LOADING;
    }

    if (state == MediaPlayer::Loaded) {
        if (m_networkState != NETWORK_IDLE)
            changeNetworkStateFromLoadingToIdle();
        m_completelyLoaded = true;
    }
}

void HTMLMediaElement::changeNetworkStateFromLoadingToIdle()
{
    m_progressEventTimer.stop();

    // Schedule one last progress event so we guarantee that at least one is fired
    // for files that load very quickly.
    scheduleEvent(EventTypeNames::progress);
    scheduleEvent(EventTypeNames::suspend);
    m_networkState = NETWORK_IDLE;
}

void HTMLMediaElement::mediaPlayerReadyStateChanged()
{
    setReadyState(m_player->readyState());
}

void HTMLMediaElement::setReadyState(MediaPlayer::ReadyState state)
{
    WTF_LOG(Media, "HTMLMediaElement::setReadyState(%d) - current state is %d,", static_cast<int>(state), static_cast<int>(m_readyState));

    // Set "wasPotentiallyPlaying" BEFORE updating m_readyState, potentiallyPlaying() uses it
    bool wasPotentiallyPlaying = potentiallyPlaying();

    ReadyState oldState = m_readyState;
    ReadyState newState = static_cast<ReadyState>(state);

    bool tracksAreReady = textTracksAreReady();

    if (newState == oldState && m_tracksAreReady == tracksAreReady)
        return;

    m_tracksAreReady = tracksAreReady;

    if (tracksAreReady)
        m_readyState = newState;
    else {
        // If a media file has text tracks the readyState may not progress beyond HAVE_FUTURE_DATA until
        // the text tracks are ready, regardless of the state of the media file.
        if (newState <= HAVE_METADATA)
            m_readyState = newState;
        else
            m_readyState = HAVE_CURRENT_DATA;
    }

    if (oldState > m_readyStateMaximum)
        m_readyStateMaximum = oldState;

    if (m_networkState == NETWORK_EMPTY)
        return;

    if (m_seeking) {
        // 4.8.10.9, step 9 note: If the media element was potentially playing immediately before
        // it started seeking, but seeking caused its readyState attribute to change to a value
        // lower than HAVE_FUTURE_DATA, then a waiting will be fired at the element.
        if (wasPotentiallyPlaying && m_readyState < HAVE_FUTURE_DATA)
            scheduleEvent(EventTypeNames::waiting);

        // 4.8.10.9 steps 12-14
        if (m_readyState >= HAVE_CURRENT_DATA)
            finishSeek();
    } else {
        if (wasPotentiallyPlaying && m_readyState < HAVE_FUTURE_DATA) {
            // 4.8.10.8
            scheduleTimeupdateEvent(false);
            scheduleEvent(EventTypeNames::waiting);
        }
    }

    if (m_readyState >= HAVE_METADATA && oldState < HAVE_METADATA) {
        prepareMediaFragmentURI();
        scheduleEvent(EventTypeNames::durationchange);
        if (isHTMLVideoElement(*this))
            scheduleEvent(EventTypeNames::resize);
        scheduleEvent(EventTypeNames::loadedmetadata);
        if (hasMediaControls())
            mediaControls()->reset();
        if (renderer())
            renderer()->updateFromElement();
    }

    bool shouldUpdateDisplayState = false;

    if (m_readyState >= HAVE_CURRENT_DATA && oldState < HAVE_CURRENT_DATA && !m_haveFiredLoadedData) {
        m_haveFiredLoadedData = true;
        shouldUpdateDisplayState = true;
        scheduleEvent(EventTypeNames::loadeddata);
        setShouldDelayLoadEvent(false);
        applyMediaFragmentURI();
    }

    bool isPotentiallyPlaying = potentiallyPlaying();
    if (m_readyState == HAVE_FUTURE_DATA && oldState <= HAVE_CURRENT_DATA && tracksAreReady) {
        scheduleEvent(EventTypeNames::canplay);
        if (isPotentiallyPlaying)
            scheduleEvent(EventTypeNames::playing);
        shouldUpdateDisplayState = true;
    }

    if (m_readyState == HAVE_ENOUGH_DATA && oldState < HAVE_ENOUGH_DATA && tracksAreReady) {
        if (oldState <= HAVE_CURRENT_DATA) {
            scheduleEvent(EventTypeNames::canplay);
            if (isPotentiallyPlaying)
                scheduleEvent(EventTypeNames::playing);
        }

        if (m_autoplaying && m_paused && autoplay() && !document().isSandboxed(SandboxAutomaticFeatures) && !m_userGestureRequiredForPlay) {
            m_paused = false;
            invalidateCachedTime();
            scheduleEvent(EventTypeNames::play);
            scheduleEvent(EventTypeNames::playing);
        }

        scheduleEvent(EventTypeNames::canplaythrough);

        shouldUpdateDisplayState = true;
    }

    if (shouldUpdateDisplayState) {
        updateDisplayState();
        if (hasMediaControls())
            mediaControls()->refreshClosedCaptionsButtonVisibility();
    }

    updatePlayState();
    updateMediaController();
    updateActiveTextTrackCues(currentTime());
}

void HTMLMediaElement::progressEventTimerFired(Timer<HTMLMediaElement>*)
{
    ASSERT(m_player);
    if (m_networkState != NETWORK_LOADING)
        return;

    double time = WTF::currentTime();
    double timedelta = time - m_previousProgressTime;

    if (m_player->didLoadingProgress()) {
        scheduleEvent(EventTypeNames::progress);
        m_previousProgressTime = time;
        m_sentStalledEvent = false;
        if (renderer())
            renderer()->updateFromElement();
    } else if (timedelta > 3.0 && !m_sentStalledEvent) {
        scheduleEvent(EventTypeNames::stalled);
        m_sentStalledEvent = true;
        setShouldDelayLoadEvent(false);
    }
}

void HTMLMediaElement::addPlayedRange(double start, double end)
{
    WTF_LOG(Media, "HTMLMediaElement::addPlayedRange(%f, %f)", start, end);
    if (!m_playedTimeRanges)
        m_playedTimeRanges = TimeRanges::create();
    m_playedTimeRanges->add(start, end);
}

bool HTMLMediaElement::supportsSave() const
{
    return m_player ? m_player->supportsSave() : false;
}

void HTMLMediaElement::prepareToPlay()
{
    WTF_LOG(Media, "HTMLMediaElement::prepareToPlay(%p)", this);
    if (m_havePreparedToPlay)
        return;
    m_havePreparedToPlay = true;

    if (m_delayingLoadForPreloadNone)
        startDelayedLoad();
}

void HTMLMediaElement::seek(double time, ExceptionState& exceptionState)
{
    WTF_LOG(Media, "HTMLMediaElement::seek(%f)", time);

    // 4.8.10.9 Seeking

    // 1 - If the media element's readyState is HAVE_NOTHING, then raise an InvalidStateError exception.
    if (m_readyState == HAVE_NOTHING || !m_player) {
        exceptionState.throwDOMException(InvalidStateError, "The element's readyState is HAVE_NOTHING.");
        return;
    }

    // If the media engine has been told to postpone loading data, let it go ahead now.
    if (m_preload < MediaPlayer::Auto && m_readyState < HAVE_FUTURE_DATA)
        prepareToPlay();

    // Get the current time before setting m_seeking, m_lastSeekTime is returned once it is set.
    refreshCachedTime();
    double now = currentTime();

    // 2 - If the element's seeking IDL attribute is true, then another instance of this algorithm is
    // already running. Abort that other instance of the algorithm without waiting for the step that
    // it is running to complete.
    // Nothing specific to be done here.

    // 3 - Set the seeking IDL attribute to true.
    // The flag will be cleared when the engine tells us the time has actually changed.
    m_seeking = true;

    // 5 - If the new playback position is later than the end of the media resource, then let it be the end
    // of the media resource instead.
    time = min(time, duration());

    // 6 - If the new playback position is less than the earliest possible position, let it be that position instead.
    time = max(time, 0.0);

    // Ask the media engine for the time value in the movie's time scale before comparing with current time. This
    // is necessary because if the seek time is not equal to currentTime but the delta is less than the movie's
    // time scale, we will ask the media engine to "seek" to the current movie time, which may be a noop and
    // not generate a timechanged callback. This means m_seeking will never be cleared and we will never
    // fire a 'seeked' event.
#if !LOG_DISABLED
    double mediaTime = m_player->mediaTimeForTimeValue(time);
    if (time != mediaTime)
        WTF_LOG(Media, "HTMLMediaElement::seek(%f) - media timeline equivalent is %f", time, mediaTime);
#endif
    time = m_player->mediaTimeForTimeValue(time);

    // 7 - If the (possibly now changed) new playback position is not in one of the ranges given in the
    // seekable attribute, then let it be the position in one of the ranges given in the seekable attribute
    // that is the nearest to the new playback position. ... If there are no ranges given in the seekable
    // attribute then set the seeking IDL attribute to false and abort these steps.
    RefPtr<TimeRanges> seekableRanges = seekable();

    // Short circuit seeking to the current time by just firing the events if no seek is required.
    // Don't skip calling the media engine if we are in poster mode because a seek should always
    // cancel poster display.
    bool noSeekRequired = !seekableRanges->length() || (time == now && displayMode() != Poster);

    // Always notify the media engine of a seek if the source is not closed. This ensures that the source is
    // always in a flushed state when the 'seeking' event fires.
    if (m_mediaSource && m_mediaSource->isClosed())
        noSeekRequired = false;

    if (noSeekRequired) {
        if (time == now) {
            scheduleEvent(EventTypeNames::seeking);
            // FIXME: There must be a stable state before timeupdate+seeked are dispatched and seeking
            // is reset to false. See http://crbug.com/266631
            scheduleTimeupdateEvent(false);
            scheduleEvent(EventTypeNames::seeked);
        }
        m_seeking = false;
        return;
    }
    time = seekableRanges->nearest(time);

    if (m_playing) {
        if (m_lastSeekTime < now)
            addPlayedRange(m_lastSeekTime, now);
    }
    m_lastSeekTime = time;
    m_sentEndEvent = false;

    // 8 - Queue a task to fire a simple event named seeking at the element.
    scheduleEvent(EventTypeNames::seeking);

    // 9 - Set the current playback position to the given new playback position
    m_player->seek(time);

    // 10-14 are handled, if necessary, when the engine signals a readystate change or otherwise
    // satisfies seek completion and signals a time change.
}

void HTMLMediaElement::finishSeek()
{
    WTF_LOG(Media, "HTMLMediaElement::finishSeek");

    // 4.8.10.9 Seeking completion
    // 12 - Set the seeking IDL attribute to false.
    m_seeking = false;

    // 13 - Queue a task to fire a simple event named timeupdate at the element.
    scheduleTimeupdateEvent(false);

    // 14 - Queue a task to fire a simple event named seeked at the element.
    scheduleEvent(EventTypeNames::seeked);

    setDisplayMode(Video);
}

HTMLMediaElement::ReadyState HTMLMediaElement::readyState() const
{
    return m_readyState;
}

bool HTMLMediaElement::hasAudio() const
{
    return m_player ? m_player->hasAudio() : false;
}

bool HTMLMediaElement::seeking() const
{
    return m_seeking;
}

void HTMLMediaElement::refreshCachedTime() const
{
    m_cachedTime = m_player->currentTime();
    m_cachedTimeWallClockUpdateTime = WTF::currentTime();
}

void HTMLMediaElement::invalidateCachedTime()
{
    WTF_LOG(Media, "HTMLMediaElement::invalidateCachedTime");

    // Don't try to cache movie time when playback first starts as the time reported by the engine
    // sometimes fluctuates for a short amount of time, so the cached time will be off if we take it
    // too early.
    static const double minimumTimePlayingBeforeCacheSnapshot = 0.5;

    m_minimumWallClockTimeToCacheMediaTime = WTF::currentTime() + minimumTimePlayingBeforeCacheSnapshot;
    m_cachedTime = MediaPlayer::invalidTime();
}

// playback state
double HTMLMediaElement::currentTime() const
{
#if LOG_CACHED_TIME_WARNINGS
    static const double minCachedDeltaForWarning = 0.01;
#endif

    if (!m_player)
        return 0;

    if (m_seeking) {
        WTF_LOG(Media, "HTMLMediaElement::currentTime - seeking, returning %f", m_lastSeekTime);
        return m_lastSeekTime;
    }

    if (m_cachedTime != MediaPlayer::invalidTime() && m_paused) {
#if LOG_CACHED_TIME_WARNINGS
        double delta = m_cachedTime - m_player->currentTime();
        if (delta > minCachedDeltaForWarning)
            WTF_LOG(Media, "HTMLMediaElement::currentTime - WARNING, cached time is %f seconds off of media time when paused", delta);
#endif
        return m_cachedTime;
    }

    refreshCachedTime();

    return m_cachedTime;
}

void HTMLMediaElement::setCurrentTime(double time, ExceptionState& exceptionState)
{
    // FIXME: generated bindings should check isfinite: http://crbug.com/354298
    if (!std::isfinite(time)) {
        exceptionState.throwTypeError(ExceptionMessages::notAFiniteNumber(time));
        return;
    }
    if (m_mediaController) {
        exceptionState.throwDOMException(InvalidStateError, "The element is slaved to a MediaController.");
        return;
    }
    seek(time, exceptionState);
}

double HTMLMediaElement::duration() const
{
    if (!m_player || m_readyState < HAVE_METADATA)
        return numeric_limits<double>::quiet_NaN();

    // FIXME: Refactor so m_duration is kept current (in both MSE and
    // non-MSE cases) once we have transitioned from HAVE_NOTHING ->
    // HAVE_METADATA. Currently, m_duration may be out of date for at least MSE
    // case because MediaSourceBase and SourceBuffer do not notify the element
    // directly upon duration changes caused by endOfStream, remove, or append
    // operations; rather the notification is triggered by the WebMediaPlayer
    // implementation observing that the underlying engine has updated duration
    // and notifying the element to consult its MediaSource for current
    // duration. See http://crbug.com/266644

    if (m_mediaSource)
        return m_mediaSource->duration();

    return m_player->duration();
}

bool HTMLMediaElement::paused() const
{
    return m_paused;
}

double HTMLMediaElement::defaultPlaybackRate() const
{
    return m_defaultPlaybackRate;
}

void HTMLMediaElement::setDefaultPlaybackRate(double rate, ExceptionState& exceptionState)
{
    // FIXME: generated bindings should check isfinite: http://crbug.com/354298
    if (!std::isfinite(rate)) {
        exceptionState.throwTypeError(ExceptionMessages::notAFiniteNumber(rate));
        return;
    }
    if (m_defaultPlaybackRate != rate) {
        m_defaultPlaybackRate = rate;
        scheduleEvent(EventTypeNames::ratechange);
    }
}

double HTMLMediaElement::playbackRate() const
{
    return m_playbackRate;
}

void HTMLMediaElement::setPlaybackRate(double rate, ExceptionState& exceptionState)
{
    WTF_LOG(Media, "HTMLMediaElement::setPlaybackRate(%f)", rate);

    // FIXME: generated bindings should check isfinite: http://crbug.com/354298
    if (!std::isfinite(rate)) {
        exceptionState.throwTypeError(ExceptionMessages::notAFiniteNumber(rate));
        return;
    }

    if (m_playbackRate != rate) {
        m_playbackRate = rate;
        invalidateCachedTime();
        scheduleEvent(EventTypeNames::ratechange);
    }

    if (m_player && potentiallyPlaying() && m_player->rate() != rate && !m_mediaController)
        m_player->setRate(rate);
}

void HTMLMediaElement::updatePlaybackRate()
{
    double effectiveRate = m_mediaController ? m_mediaController->playbackRate() : m_playbackRate;
    if (m_player && potentiallyPlaying() && m_player->rate() != effectiveRate)
        m_player->setRate(effectiveRate);
}

bool HTMLMediaElement::ended() const
{
    // 4.8.10.8 Playing the media resource
    // The ended attribute must return true if the media element has ended
    // playback and the direction of playback is forwards, and false otherwise.
    return endedPlayback() && m_playbackRate > 0;
}

bool HTMLMediaElement::autoplay() const
{
    return fastHasAttribute(autoplayAttr);
}

String HTMLMediaElement::preload() const
{
    switch (m_preload) {
    case MediaPlayer::None:
        return "none";
        break;
    case MediaPlayer::MetaData:
        return "metadata";
        break;
    case MediaPlayer::Auto:
        return "auto";
        break;
    }

    ASSERT_NOT_REACHED();
    return String();
}

void HTMLMediaElement::setPreload(const AtomicString& preload)
{
    WTF_LOG(Media, "HTMLMediaElement::setPreload(%s)", preload.utf8().data());
    setAttribute(preloadAttr, preload);
}

void HTMLMediaElement::play()
{
    WTF_LOG(Media, "HTMLMediaElement::play()");

    if (m_userGestureRequiredForPlay && !UserGestureIndicator::processingUserGesture())
        return;
    if (UserGestureIndicator::processingUserGesture())
        m_userGestureRequiredForPlay = false;

    playInternal();
}

void HTMLMediaElement::playInternal()
{
    WTF_LOG(Media, "HTMLMediaElement::playInternal");

    // 4.8.10.9. Playing the media resource
    if (!m_player || m_networkState == NETWORK_EMPTY)
        scheduleDelayedAction(LoadMediaResource);

    if (endedPlayback())
        seek(0, IGNORE_EXCEPTION);

    if (m_mediaController)
        m_mediaController->bringElementUpToSpeed(this);

    if (m_paused) {
        m_paused = false;
        invalidateCachedTime();
        scheduleEvent(EventTypeNames::play);

        if (m_readyState <= HAVE_CURRENT_DATA)
            scheduleEvent(EventTypeNames::waiting);
        else if (m_readyState >= HAVE_FUTURE_DATA)
            scheduleEvent(EventTypeNames::playing);
    }
    m_autoplaying = false;

    updatePlayState();
    updateMediaController();
}

void HTMLMediaElement::pause()
{
    WTF_LOG(Media, "HTMLMediaElement::pause()");

    if (!m_player || m_networkState == NETWORK_EMPTY)
        scheduleDelayedAction(LoadMediaResource);

    m_autoplaying = false;

    if (!m_paused) {
        m_paused = true;
        scheduleTimeupdateEvent(false);
        scheduleEvent(EventTypeNames::pause);
    }

    updatePlayState();
}

void HTMLMediaElement::closeMediaSource()
{
    if (!m_mediaSource)
        return;

    m_mediaSource->close();
    m_mediaSource = nullptr;
}

bool HTMLMediaElement::loop() const
{
    return fastHasAttribute(loopAttr);
}

void HTMLMediaElement::setLoop(bool b)
{
    WTF_LOG(Media, "HTMLMediaElement::setLoop(%s)", boolString(b));
    setBooleanAttribute(loopAttr, b);
}

bool HTMLMediaElement::controls() const
{
    LocalFrame* frame = document().frame();

    // always show controls when scripting is disabled
    if (frame && !frame->script().canExecuteScripts(NotAboutToExecuteScript))
        return true;

    // Always show controls when in full screen mode.
    if (isFullscreen())
        return true;

    return fastHasAttribute(controlsAttr);
}

void HTMLMediaElement::setControls(bool b)
{
    WTF_LOG(Media, "HTMLMediaElement::setControls(%s)", boolString(b));
    setBooleanAttribute(controlsAttr, b);
}

double HTMLMediaElement::volume() const
{
    return m_volume;
}

void HTMLMediaElement::setVolume(double vol, ExceptionState& exceptionState)
{
    WTF_LOG(Media, "HTMLMediaElement::setVolume(%f)", vol);

    // FIXME: generated bindings should check isfinite: http://crbug.com/354298
    if (!std::isfinite(vol)) {
        exceptionState.throwTypeError(ExceptionMessages::notAFiniteNumber(vol));
        return;
    }

    if (vol < 0.0f || vol > 1.0f) {
        exceptionState.throwDOMException(IndexSizeError, ExceptionMessages::indexOutsideRange("volume", vol, 0.0, ExceptionMessages::InclusiveBound, 1.0, ExceptionMessages::InclusiveBound));
        return;
    }

    if (m_volume != vol) {
        m_volume = vol;
        updateVolume();
        scheduleEvent(EventTypeNames::volumechange);
    }
}

bool HTMLMediaElement::muted() const
{
    return m_muted;
}

void HTMLMediaElement::setMuted(bool muted)
{
    WTF_LOG(Media, "HTMLMediaElement::setMuted(%s)", boolString(muted));

    if (m_muted == muted)
        return;

    m_muted = muted;

    updateVolume();

    scheduleEvent(EventTypeNames::volumechange);
}

// The spec says to fire periodic timeupdate events (those sent while playing) every
// "15 to 250ms", we choose the slowest frequency
static const double maxTimeupdateEventFrequency = 0.25;

void HTMLMediaElement::startPlaybackProgressTimer()
{
    if (m_playbackProgressTimer.isActive())
        return;

    m_previousProgressTime = WTF::currentTime();
    m_playbackProgressTimer.startRepeating(maxTimeupdateEventFrequency, FROM_HERE);
}

void HTMLMediaElement::playbackProgressTimerFired(Timer<HTMLMediaElement>*)
{
    ASSERT(m_player);

    if (m_fragmentEndTime != MediaPlayer::invalidTime() && currentTime() >= m_fragmentEndTime && m_playbackRate > 0) {
        m_fragmentEndTime = MediaPlayer::invalidTime();
        if (!m_mediaController && !m_paused) {
            UseCounter::count(document(), UseCounter::HTMLMediaElementPauseAtFragmentEnd);
            // changes paused to true and fires a simple event named pause at the media element.
            pause();
        }
    }

    if (!m_seeking)
        scheduleTimeupdateEvent(true);

    if (!m_playbackRate)
        return;

    if (!m_paused && hasMediaControls())
        mediaControls()->playbackProgressed();

    updateActiveTextTrackCues(currentTime());
}

void HTMLMediaElement::scheduleTimeupdateEvent(bool periodicEvent)
{
    double now = WTF::currentTime();
    double timedelta = now - m_lastTimeUpdateEventWallTime;

    // throttle the periodic events
    if (periodicEvent && timedelta < maxTimeupdateEventFrequency)
        return;

    // Some media engines make multiple "time changed" callbacks at the same time, but we only want one
    // event at a given time so filter here
    double movieTime = currentTime();
    if (movieTime != m_lastTimeUpdateEventMovieTime) {
        scheduleEvent(EventTypeNames::timeupdate);
        m_lastTimeUpdateEventWallTime = now;
        m_lastTimeUpdateEventMovieTime = movieTime;
    }
}

bool HTMLMediaElement::togglePlayStateWillPlay() const
{
    if (m_mediaController)
        return m_mediaController->paused() || m_mediaController->isRestrained();
    return paused();
}

void HTMLMediaElement::togglePlayState()
{
    // The activation behavior of a media element that is exposing a user interface to the user
    if (m_mediaController) {
        if (m_mediaController->isRestrained())
            m_mediaController->play();
        else if (m_mediaController->paused())
            m_mediaController->unpause();
        else
            m_mediaController->pause();
    } else {
        if (paused())
            play();
        else
            pause();
    }
}

void HTMLMediaElement::mediaPlayerDidAddTextTrack(WebInbandTextTrack* webTrack)
{
    // 4.8.10.12.2 Sourcing in-band text tracks
    // 1. Associate the relevant data with a new text track and its corresponding new TextTrack object.
    RefPtr<InbandTextTrack> textTrack = InbandTextTrack::create(document(), webTrack);

    // 2. Set the new text track's kind, label, and language based on the semantics of the relevant data,
    // as defined by the relevant specification. If there is no label in that data, then the label must
    // be set to the empty string.
    // 3. Associate the text track list of cues with the rules for updating the text track rendering appropriate
    // for the format in question.
    // 4. If the new text track's kind is metadata, then set the text track in-band metadata track dispatch type
    // as follows, based on the type of the media resource:
    // 5. Populate the new text track's list of cues with the cues parsed so far, folllowing the guidelines for exposing
    // cues, and begin updating it dynamically as necessary.
    //   - Thess are all done by the media engine.

    // 6. Set the new text track's readiness state to loaded.
    textTrack->setReadinessState(TextTrack::Loaded);

    // 7. Set the new text track's mode to the mode consistent with the user's preferences and the requirements of
    // the relevant specification for the data.
    //  - This will happen in configureTextTracks()
    scheduleDelayedAction(LoadTextTrackResource);

    // 8. Add the new text track to the media element's list of text tracks.
    // 9. Fire an event with the name addtrack, that does not bubble and is not cancelable, and that uses the TrackEvent
    // interface, with the track attribute initialized to the text track's TextTrack object, at the media element's
    // textTracks attribute's TextTrackList object.
    addTextTrack(textTrack.get());
}

void HTMLMediaElement::mediaPlayerDidRemoveTextTrack(WebInbandTextTrack* webTrack)
{
    if (!m_textTracks)
        return;

    // This cast is safe because we created the InbandTextTrack with the WebInbandTextTrack
    // passed to mediaPlayerDidAddTextTrack.
    RefPtr<InbandTextTrack> textTrack = static_cast<InbandTextTrack*>(webTrack->client());
    if (!textTrack)
        return;

    removeTextTrack(textTrack.get());
}

void HTMLMediaElement::closeCaptionTracksChanged()
{
    if (hasMediaControls())
        mediaControls()->closedCaptionTracksChanged();
}

void HTMLMediaElement::addTextTrack(TextTrack* track)
{
    textTracks()->append(track);

    closeCaptionTracksChanged();
}

void HTMLMediaElement::removeTextTrack(TextTrack* track)
{
    TrackDisplayUpdateScope scope(this);
    m_textTracks->remove(track);

    closeCaptionTracksChanged();
}

void HTMLMediaElement::forgetResourceSpecificTracks()
{
    if (m_textTracks) {
        TrackDisplayUpdateScope scope(this);
        m_textTracks->removeAllInbandTracks();
        closeCaptionTracksChanged();
    }
}

PassRefPtr<TextTrack> HTMLMediaElement::addTextTrack(const AtomicString& kind, const AtomicString& label, const AtomicString& language, ExceptionState& exceptionState)
{
    // 4.8.10.12.4 Text track API
    // The addTextTrack(kind, label, language) method of media elements, when invoked, must run the following steps:

    // 1. If kind is not one of the following strings, then throw a SyntaxError exception and abort these steps
    if (!TextTrack::isValidKindKeyword(kind)) {
        exceptionState.throwDOMException(SyntaxError, "The 'kind' provided ('" + kind + "') is invalid.");
        return nullptr;
    }

    // 2. If the label argument was omitted, let label be the empty string.
    // 3. If the language argument was omitted, let language be the empty string.
    // 4. Create a new TextTrack object.

    // 5. Create a new text track corresponding to the new object, and set its text track kind to kind, its text
    // track label to label, its text track language to language...
    RefPtr<TextTrack> textTrack = TextTrack::create(document(), kind, label, language);

    // Note, due to side effects when changing track parameters, we have to
    // first append the track to the text track list.

    // 6. Add the new text track to the media element's list of text tracks.
    addTextTrack(textTrack.get());

    // ... its text track readiness state to the text track loaded state ...
    textTrack->setReadinessState(TextTrack::Loaded);

    // ... its text track mode to the text track hidden mode, and its text track list of cues to an empty list ...
    textTrack->setMode(TextTrack::hiddenKeyword());

    return textTrack.release();
}

TextTrackList* HTMLMediaElement::textTracks()
{
    if (!m_textTracks)
        m_textTracks = TextTrackList::create(this);

    return m_textTracks.get();
}

void HTMLMediaElement::didAddTrackElement(HTMLTrackElement* trackElement)
{
    // 4.8.10.12.3 Sourcing out-of-band text tracks
    // When a track element's parent element changes and the new parent is a media element,
    // then the user agent must add the track element's corresponding text track to the
    // media element's list of text tracks ... [continues in TextTrackList::append]
    RefPtr<TextTrack> textTrack = trackElement->track();
    if (!textTrack)
        return;

    addTextTrack(textTrack.get());

    // Do not schedule the track loading until parsing finishes so we don't start before all tracks
    // in the markup have been added.
    if (isFinishedParsingChildren())
        scheduleDelayedAction(LoadTextTrackResource);

    if (hasMediaControls())
        mediaControls()->closedCaptionTracksChanged();
}

void HTMLMediaElement::didRemoveTrackElement(HTMLTrackElement* trackElement)
{
#if !LOG_DISABLED
    KURL url = trackElement->getNonEmptyURLAttribute(srcAttr);
    WTF_LOG(Media, "HTMLMediaElement::didRemoveTrackElement - 'src' is %s", urlForLoggingMedia(url).utf8().data());
#endif

    RefPtr<TextTrack> textTrack = trackElement->track();
    if (!textTrack)
        return;

    textTrack->setHasBeenConfigured(false);

    if (!m_textTracks)
        return;

    // 4.8.10.12.3 Sourcing out-of-band text tracks
    // When a track element's parent element changes and the old parent was a media element,
    // then the user agent must remove the track element's corresponding text track from the
    // media element's list of text tracks.
    removeTextTrack(textTrack.get());

    size_t index = m_textTracksWhenResourceSelectionBegan.find(textTrack.get());
    if (index != kNotFound)
        m_textTracksWhenResourceSelectionBegan.remove(index);
}

static int textTrackLanguageSelectionScore(const TextTrack& track)
{
    if (track.language().isEmpty())
        return 0;

    Vector<AtomicString> languages = userPreferredLanguages();
    size_t languageMatchIndex = indexOfBestMatchingLanguageInList(track.language(), languages);
    if (languageMatchIndex >= languages.size())
        return 0;

    // Matching a track language is more important than matching track type, so this multiplier must be
    // greater than the maximum value returned by textTrackSelectionScore.
    return (languages.size() - languageMatchIndex) * 10;
}

static int textTrackSelectionScore(const TextTrack& track, Settings* settings)
{
    int trackScore = 0;

    if (!settings)
        return trackScore;

    if (track.kind() != TextTrack::captionsKeyword() && track.kind() != TextTrack::subtitlesKeyword())
        return trackScore;

    if (track.kind() == TextTrack::subtitlesKeyword() && settings->shouldDisplaySubtitles())
        trackScore = 1;
    else if (track.kind() == TextTrack::captionsKeyword() && settings->shouldDisplayCaptions())
        trackScore = 1;

    return trackScore + textTrackLanguageSelectionScore(track);
}

void HTMLMediaElement::configureTextTrackGroup(const TrackGroup& group)
{
    ASSERT(group.tracks.size());

    WTF_LOG(Media, "HTMLMediaElement::configureTextTrackGroup(%d)", group.kind);

    Settings* settings = document().settings();

    // First, find the track in the group that should be enabled (if any).
    Vector<RefPtr<TextTrack> > currentlyEnabledTracks;
    RefPtr<TextTrack> trackToEnable;
    RefPtr<TextTrack> defaultTrack;
    RefPtr<TextTrack> fallbackTrack;
    int highestTrackScore = 0;
    for (size_t i = 0; i < group.tracks.size(); ++i) {
        RefPtr<TextTrack> textTrack = group.tracks[i];

        if (m_processingPreferenceChange && textTrack->mode() == TextTrack::showingKeyword())
            currentlyEnabledTracks.append(textTrack);

        int trackScore = textTrackSelectionScore(*textTrack, settings);
        if (trackScore) {
            // * If the text track kind is { [subtitles or captions] [descriptions] } and the user has indicated an interest in having a
            // track with this text track kind, text track language, and text track label enabled, and there is no
            // other text track in the media element's list of text tracks with a text track kind of either subtitles
            // or captions whose text track mode is showing
            // ...
            // * If the text track kind is chapters and the text track language is one that the user agent has reason
            // to believe is appropriate for the user, and there is no other text track in the media element's list of
            // text tracks with a text track kind of chapters whose text track mode is showing
            //    Let the text track mode be showing.
            if (trackScore > highestTrackScore) {
                highestTrackScore = trackScore;
                trackToEnable = textTrack;
            }

            if (!defaultTrack && textTrack->isDefault())
                defaultTrack = textTrack;
            if (!defaultTrack && !fallbackTrack)
                fallbackTrack = textTrack;
        } else if (!group.visibleTrack && !defaultTrack && textTrack->isDefault()) {
            // * If the track element has a default attribute specified, and there is no other text track in the media
            // element's list of text tracks whose text track mode is showing or showing by default
            //    Let the text track mode be showing by default.
            defaultTrack = textTrack;
        }
    }

    if (!trackToEnable && defaultTrack)
        trackToEnable = defaultTrack;

    // If no track matches the user's preferred language and non was marked 'default', enable the first track
    // because the user has explicitly stated a preference for this kind of track.
    if (!fallbackTrack && m_closedCaptionsVisible && group.kind == TrackGroup::CaptionsAndSubtitles)
        fallbackTrack = group.tracks[0];

    if (!trackToEnable && fallbackTrack)
        trackToEnable = fallbackTrack;

    if (currentlyEnabledTracks.size()) {
        for (size_t i = 0; i < currentlyEnabledTracks.size(); ++i) {
            RefPtr<TextTrack> textTrack = currentlyEnabledTracks[i];
            if (textTrack != trackToEnable)
                textTrack->setMode(TextTrack::disabledKeyword());
        }
    }

    if (trackToEnable)
        trackToEnable->setMode(TextTrack::showingKeyword());
}

void HTMLMediaElement::configureTextTracks()
{
    TrackGroup captionAndSubtitleTracks(TrackGroup::CaptionsAndSubtitles);
    TrackGroup descriptionTracks(TrackGroup::Description);
    TrackGroup chapterTracks(TrackGroup::Chapter);
    TrackGroup metadataTracks(TrackGroup::Metadata);
    TrackGroup otherTracks(TrackGroup::Other);

    if (!m_textTracks)
        return;

    for (size_t i = 0; i < m_textTracks->length(); ++i) {
        RefPtr<TextTrack> textTrack = m_textTracks->item(i);
        if (!textTrack)
            continue;

        String kind = textTrack->kind();
        TrackGroup* currentGroup;
        if (kind == TextTrack::subtitlesKeyword() || kind == TextTrack::captionsKeyword())
            currentGroup = &captionAndSubtitleTracks;
        else if (kind == TextTrack::descriptionsKeyword())
            currentGroup = &descriptionTracks;
        else if (kind == TextTrack::chaptersKeyword())
            currentGroup = &chapterTracks;
        else if (kind == TextTrack::metadataKeyword())
            currentGroup = &metadataTracks;
        else
            currentGroup = &otherTracks;

        if (!currentGroup->visibleTrack && textTrack->mode() == TextTrack::showingKeyword())
            currentGroup->visibleTrack = textTrack;
        if (!currentGroup->defaultTrack && textTrack->isDefault())
            currentGroup->defaultTrack = textTrack;

        // Do not add this track to the group if it has already been automatically configured
        // as we only want to call configureTextTrack once per track so that adding another
        // track after the initial configuration doesn't reconfigure every track - only those
        // that should be changed by the new addition. For example all metadata tracks are
        // disabled by default, and we don't want a track that has been enabled by script
        // to be disabled automatically when a new metadata track is added later.
        if (textTrack->hasBeenConfigured())
            continue;

        if (textTrack->language().length())
            currentGroup->hasSrcLang = true;
        currentGroup->tracks.append(textTrack);
    }

    if (captionAndSubtitleTracks.tracks.size())
        configureTextTrackGroup(captionAndSubtitleTracks);
    if (descriptionTracks.tracks.size())
        configureTextTrackGroup(descriptionTracks);
    if (chapterTracks.tracks.size())
        configureTextTrackGroup(chapterTracks);
    if (metadataTracks.tracks.size())
        configureTextTrackGroup(metadataTracks);
    if (otherTracks.tracks.size())
        configureTextTrackGroup(otherTracks);

    if (hasMediaControls())
        mediaControls()->closedCaptionTracksChanged();
}

bool HTMLMediaElement::havePotentialSourceChild()
{
    // Stash the current <source> node and next nodes so we can restore them after checking
    // to see there is another potential.
    RefPtr<HTMLSourceElement> currentSourceNode = m_currentSourceNode;
    RefPtr<Node> nextNode = m_nextChildNodeToConsider;

    KURL nextURL = selectNextSourceChild(0, 0, DoNothing);

    m_currentSourceNode = currentSourceNode;
    m_nextChildNodeToConsider = nextNode;

    return nextURL.isValid();
}

KURL HTMLMediaElement::selectNextSourceChild(ContentType* contentType, String* keySystem, InvalidURLAction actionIfInvalid)
{
#if !LOG_DISABLED
    // Don't log if this was just called to find out if there are any valid <source> elements.
    bool shouldLog = actionIfInvalid != DoNothing;
    if (shouldLog)
        WTF_LOG(Media, "HTMLMediaElement::selectNextSourceChild");
#endif

    if (!m_nextChildNodeToConsider) {
#if !LOG_DISABLED
        if (shouldLog)
            WTF_LOG(Media, "HTMLMediaElement::selectNextSourceChild -> 0x0000, \"\"");
#endif
        return KURL();
    }

    KURL mediaURL;
    Node* node;
    HTMLSourceElement* source = 0;
    String type;
    String system;
    bool lookingForStartNode = m_nextChildNodeToConsider;
    bool canUseSourceElement = false;

    NodeVector potentialSourceNodes;
    getChildNodes(*this, potentialSourceNodes);

    for (unsigned i = 0; !canUseSourceElement && i < potentialSourceNodes.size(); ++i) {
        node = potentialSourceNodes[i].get();
        if (lookingForStartNode && m_nextChildNodeToConsider != node)
            continue;
        lookingForStartNode = false;

        if (!isHTMLSourceElement(*node))
            continue;
        if (node->parentNode() != this)
            continue;

        source = toHTMLSourceElement(node);

        // If candidate does not have a src attribute, or if its src attribute's value is the empty string ... jump down to the failed step below
        mediaURL = source->getNonEmptyURLAttribute(srcAttr);
#if !LOG_DISABLED
        if (shouldLog)
            WTF_LOG(Media, "HTMLMediaElement::selectNextSourceChild - 'src' is %s", urlForLoggingMedia(mediaURL).utf8().data());
#endif
        if (mediaURL.isEmpty())
            goto check_again;

        type = source->type();
        // FIXME(82965): Add support for keySystem in <source> and set system from source.
        if (type.isEmpty() && mediaURL.protocolIsData())
            type = mimeTypeFromDataURL(mediaURL);
        if (!type.isEmpty() || !system.isEmpty()) {
#if !LOG_DISABLED
            if (shouldLog)
                WTF_LOG(Media, "HTMLMediaElement::selectNextSourceChild - 'type' is '%s' - key system is '%s'", type.utf8().data(), system.utf8().data());
#endif
            if (!supportsType(ContentType(type), system))
                goto check_again;
        }

        // Is it safe to load this url?
        if (!isSafeToLoadURL(mediaURL, actionIfInvalid))
            goto check_again;

        // Making it this far means the <source> looks reasonable.
        canUseSourceElement = true;

check_again:
        if (!canUseSourceElement && actionIfInvalid == Complain && source)
            source->scheduleErrorEvent();
    }

    if (canUseSourceElement) {
        if (contentType)
            *contentType = ContentType(type);
        if (keySystem)
            *keySystem = system;
        m_currentSourceNode = source;
        m_nextChildNodeToConsider = source->nextSibling();
    } else {
        m_currentSourceNode = nullptr;
        m_nextChildNodeToConsider = nullptr;
    }

#if !LOG_DISABLED
    if (shouldLog)
        WTF_LOG(Media, "HTMLMediaElement::selectNextSourceChild -> %p, %s", m_currentSourceNode.get(), canUseSourceElement ? urlForLoggingMedia(mediaURL).utf8().data() : "");
#endif
    return canUseSourceElement ? mediaURL : KURL();
}

void HTMLMediaElement::sourceWasAdded(HTMLSourceElement* source)
{
    WTF_LOG(Media, "HTMLMediaElement::sourceWasAdded(%p)", source);

#if !LOG_DISABLED
    KURL url = source->getNonEmptyURLAttribute(srcAttr);
    WTF_LOG(Media, "HTMLMediaElement::sourceWasAdded - 'src' is %s", urlForLoggingMedia(url).utf8().data());
#endif

    // We should only consider a <source> element when there is not src attribute at all.
    if (fastHasAttribute(srcAttr))
        return;

    // 4.8.8 - If a source element is inserted as a child of a media element that has no src
    // attribute and whose networkState has the value NETWORK_EMPTY, the user agent must invoke
    // the media element's resource selection algorithm.
    if (networkState() == HTMLMediaElement::NETWORK_EMPTY) {
        scheduleDelayedAction(LoadMediaResource);
        m_nextChildNodeToConsider = source;
        return;
    }

    if (m_currentSourceNode && source == m_currentSourceNode->nextSibling()) {
        WTF_LOG(Media, "HTMLMediaElement::sourceWasAdded - <source> inserted immediately after current source");
        m_nextChildNodeToConsider = source;
        return;
    }

    if (m_nextChildNodeToConsider)
        return;

    // 4.8.9.5, resource selection algorithm, source elements section:
    // 21. Wait until the node after pointer is a node other than the end of the list. (This step might wait forever.)
    // 22. Asynchronously await a stable state...
    // 23. Set the element's delaying-the-load-event flag back to true (this delays the load event again, in case
    // it hasn't been fired yet).
    setShouldDelayLoadEvent(true);

    // 24. Set the networkState back to NETWORK_LOADING.
    m_networkState = NETWORK_LOADING;

    // 25. Jump back to the find next candidate step above.
    m_nextChildNodeToConsider = source;
    scheduleNextSourceChild();
}

void HTMLMediaElement::sourceWasRemoved(HTMLSourceElement* source)
{
    WTF_LOG(Media, "HTMLMediaElement::sourceWasRemoved(%p)", source);

#if !LOG_DISABLED
    KURL url = source->getNonEmptyURLAttribute(srcAttr);
    WTF_LOG(Media, "HTMLMediaElement::sourceWasRemoved - 'src' is %s", urlForLoggingMedia(url).utf8().data());
#endif

    if (source != m_currentSourceNode && source != m_nextChildNodeToConsider)
        return;

    if (source == m_nextChildNodeToConsider) {
        if (m_currentSourceNode)
            m_nextChildNodeToConsider = m_currentSourceNode->nextSibling();
        WTF_LOG(Media, "HTMLMediaElement::sourceRemoved - m_nextChildNodeToConsider set to %p", m_nextChildNodeToConsider.get());
    } else if (source == m_currentSourceNode) {
        // Clear the current source node pointer, but don't change the movie as the spec says:
        // 4.8.8 - Dynamically modifying a source element and its attribute when the element is already
        // inserted in a video or audio element will have no effect.
        m_currentSourceNode = nullptr;
        WTF_LOG(Media, "HTMLMediaElement::sourceRemoved - m_currentSourceNode set to 0");
    }
}

void HTMLMediaElement::mediaPlayerTimeChanged()
{
    WTF_LOG(Media, "HTMLMediaElement::mediaPlayerTimeChanged");

    updateActiveTextTrackCues(currentTime());

    invalidateCachedTime();

    // 4.8.10.9 steps 12-14. Needed if no ReadyState change is associated with the seek.
    if (m_seeking && m_readyState >= HAVE_CURRENT_DATA && !m_player->seeking())
        finishSeek();

    // Always call scheduleTimeupdateEvent when the media engine reports a time discontinuity,
    // it will only queue a 'timeupdate' event if we haven't already posted one at the current
    // movie time.
    scheduleTimeupdateEvent(false);

    double now = currentTime();
    double dur = duration();

    // When the current playback position reaches the end of the media resource when the direction of
    // playback is forwards, then the user agent must follow these steps:
    if (!std::isnan(dur) && dur && now >= dur && m_playbackRate > 0) {
        // If the media element has a loop attribute specified and does not have a current media controller,
        if (loop() && !m_mediaController) {
            m_sentEndEvent = false;
            //  then seek to the earliest possible position of the media resource and abort these steps.
            seek(0, IGNORE_EXCEPTION);
        } else {
            // If the media element does not have a current media controller, and the media element
            // has still ended playback, and the direction of playback is still forwards, and paused
            // is false,
            if (!m_mediaController && !m_paused) {
                // changes paused to true and fires a simple event named pause at the media element.
                m_paused = true;
                scheduleEvent(EventTypeNames::pause);
            }
            // Queue a task to fire a simple event named ended at the media element.
            if (!m_sentEndEvent) {
                m_sentEndEvent = true;
                scheduleEvent(EventTypeNames::ended);
            }
            // If the media element has a current media controller, then report the controller state
            // for the media element's current media controller.
            updateMediaController();
        }
    }
    else
        m_sentEndEvent = false;

    updatePlayState();
}

void HTMLMediaElement::mediaPlayerDurationChanged()
{
    WTF_LOG(Media, "HTMLMediaElement::mediaPlayerDurationChanged");
    durationChanged(duration());
}

void HTMLMediaElement::durationChanged(double duration)
{
    WTF_LOG(Media, "HTMLMediaElement::durationChanged(%f)", duration);

    // Abort if duration unchanged.
    if (m_duration == duration)
        return;

    m_duration = duration;
    scheduleEvent(EventTypeNames::durationchange);

    if (hasMediaControls())
        mediaControls()->reset();
    if (renderer())
        renderer()->updateFromElement();

    if (currentTime() > duration)
        seek(duration, IGNORE_EXCEPTION);
}

void HTMLMediaElement::mediaPlayerPlaybackStateChanged()
{
    WTF_LOG(Media, "HTMLMediaElement::mediaPlayerPlaybackStateChanged");

    if (!m_player || m_pausedInternal)
        return;

    if (m_player->paused())
        pause();
    else
        playInternal();
}

void HTMLMediaElement::mediaPlayerRequestFullscreen()
{
    WTF_LOG(Media, "HTMLMediaElement::mediaPlayerRequestFullscreen");

    // The player is responsible for only invoking this callback in response to
    // user interaction or when it is technically required to play the video.
    UserGestureIndicator gestureIndicator(DefinitelyProcessingNewUserGesture);

    enterFullscreen();
}

void HTMLMediaElement::mediaPlayerRequestSeek(double time)
{
    // The player is the source of this seek request.
    if (m_mediaController) {
        m_mediaController->setCurrentTime(time, IGNORE_EXCEPTION);
        return;
    }
    setCurrentTime(time, IGNORE_EXCEPTION);
}

// MediaPlayerPresentation methods
void HTMLMediaElement::mediaPlayerRepaint()
{
    if (m_webLayer)
        m_webLayer->invalidate();

    updateDisplayState();
    if (renderer())
        renderer()->repaint();
}

void HTMLMediaElement::mediaPlayerSizeChanged()
{
    WTF_LOG(Media, "HTMLMediaElement::mediaPlayerSizeChanged");

    ASSERT(hasVideo()); // "resize" makes no sense absent video.
    if (m_readyState > HAVE_NOTHING && isHTMLVideoElement(*this))
        scheduleEvent(EventTypeNames::resize);

    if (renderer())
        renderer()->updateFromElement();
}

PassRefPtr<TimeRanges> HTMLMediaElement::buffered() const
{
    if (!m_player)
        return TimeRanges::create();

    if (m_mediaSource)
        return m_mediaSource->buffered();

    return m_player->buffered();
}

PassRefPtr<TimeRanges> HTMLMediaElement::played()
{
    if (m_playing) {
        double time = currentTime();
        if (time > m_lastSeekTime)
            addPlayedRange(m_lastSeekTime, time);
    }

    if (!m_playedTimeRanges)
        m_playedTimeRanges = TimeRanges::create();

    return m_playedTimeRanges->copy();
}

PassRefPtr<TimeRanges> HTMLMediaElement::seekable() const
{
    if (m_player) {
        double maxTimeSeekable = m_player->maxTimeSeekable();
        if (maxTimeSeekable)
            return TimeRanges::create(0, maxTimeSeekable);
    }
    return TimeRanges::create();
}

bool HTMLMediaElement::potentiallyPlaying() const
{
    // "pausedToBuffer" means the media engine's rate is 0, but only because it had to stop playing
    // when it ran out of buffered data. A movie is this state is "potentially playing", modulo the
    // checks in couldPlayIfEnoughData().
    bool pausedToBuffer = m_readyStateMaximum >= HAVE_FUTURE_DATA && m_readyState < HAVE_FUTURE_DATA;
    return (pausedToBuffer || m_readyState >= HAVE_FUTURE_DATA) && couldPlayIfEnoughData() && !isBlockedOnMediaController();
}

bool HTMLMediaElement::couldPlayIfEnoughData() const
{
    return !paused() && !endedPlayback() && !stoppedDueToErrors() && !pausedForUserInteraction();
}

bool HTMLMediaElement::endedPlayback() const
{
    double dur = duration();
    if (!m_player || std::isnan(dur))
        return false;

    // 4.8.10.8 Playing the media resource

    // A media element is said to have ended playback when the element's
    // readyState attribute is HAVE_METADATA or greater,
    if (m_readyState < HAVE_METADATA)
        return false;

    // and the current playback position is the end of the media resource and the direction
    // of playback is forwards, Either the media element does not have a loop attribute specified,
    // or the media element has a current media controller.
    double now = currentTime();
    if (m_playbackRate > 0)
        return dur > 0 && now >= dur && (!loop() || m_mediaController);

    // or the current playback position is the earliest possible position and the direction
    // of playback is backwards
    if (m_playbackRate < 0)
        return now <= 0;

    return false;
}

bool HTMLMediaElement::stoppedDueToErrors() const
{
    if (m_readyState >= HAVE_METADATA && m_error) {
        RefPtr<TimeRanges> seekableRanges = seekable();
        if (!seekableRanges->contain(currentTime()))
            return true;
    }

    return false;
}

bool HTMLMediaElement::pausedForUserInteraction() const
{
//    return !paused() && m_readyState >= HAVE_FUTURE_DATA && [UA requires a decitions from the user]
    return false;
}

void HTMLMediaElement::updateVolume()
{
    if (webMediaPlayer())
        webMediaPlayer()->setVolume(playerVolume());

    if (hasMediaControls())
        mediaControls()->updateVolume();
}

double HTMLMediaElement::playerVolume() const
{
    double volumeMultiplier = 1;
    bool shouldMute = m_muted;

    if (m_mediaController) {
        volumeMultiplier *= m_mediaController->volume();
        shouldMute = m_mediaController->muted();
    }

    return shouldMute ? 0 : m_volume * volumeMultiplier;
}

void HTMLMediaElement::updatePlayState()
{
    if (!m_player)
        return;

    if (m_pausedInternal) {
        if (!m_player->paused())
            m_player->pause();
        refreshCachedTime();
        m_playbackProgressTimer.stop();
        if (hasMediaControls())
            mediaControls()->playbackStopped();
        return;
    }

    bool shouldBePlaying = potentiallyPlaying();
    bool playerPaused = m_player->paused();

    WTF_LOG(Media, "HTMLMediaElement::updatePlayState - shouldBePlaying = %s, playerPaused = %s",
        boolString(shouldBePlaying), boolString(playerPaused));

    if (shouldBePlaying) {
        setDisplayMode(Video);
        invalidateCachedTime();

        if (playerPaused) {
            // Set rate, muted before calling play in case they were set before the media engine was setup.
            // The media engine should just stash the rate and muted values since it isn't already playing.
            m_player->setRate(m_playbackRate);
            updateVolume();

            m_player->play();
        }

        if (hasMediaControls())
            mediaControls()->playbackStarted();
        startPlaybackProgressTimer();
        m_playing = true;

    } else { // Should not be playing right now
        if (!playerPaused)
            m_player->pause();
        refreshCachedTime();

        m_playbackProgressTimer.stop();
        m_playing = false;
        double time = currentTime();
        if (time > m_lastSeekTime)
            addPlayedRange(m_lastSeekTime, time);

        if (couldPlayIfEnoughData())
            prepareToPlay();

        if (hasMediaControls())
            mediaControls()->playbackStopped();
    }

    updateMediaController();

    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::setPausedInternal(bool b)
{
    m_pausedInternal = b;
    updatePlayState();
}

void HTMLMediaElement::stopPeriodicTimers()
{
    m_progressEventTimer.stop();
    m_playbackProgressTimer.stop();
}

void HTMLMediaElement::userCancelledLoad()
{
    WTF_LOG(Media, "HTMLMediaElement::userCancelledLoad");

    // If the media data fetching process is aborted by the user:

    // 1 - The user agent should cancel the fetching process.
    clearMediaPlayer(-1);

    if (m_networkState == NETWORK_EMPTY || m_completelyLoaded)
        return;

    // 2 - Set the error attribute to a new MediaError object whose code attribute is set to MEDIA_ERR_ABORTED.
    m_error = MediaError::create(MediaError::MEDIA_ERR_ABORTED);

    // 3 - Queue a task to fire a simple event named error at the media element.
    scheduleEvent(EventTypeNames::abort);

    closeMediaSource();

    // 4 - If the media element's readyState attribute has a value equal to HAVE_NOTHING, set the
    // element's networkState attribute to the NETWORK_EMPTY value and queue a task to fire a
    // simple event named emptied at the element. Otherwise, set the element's networkState
    // attribute to the NETWORK_IDLE value.
    if (m_readyState == HAVE_NOTHING) {
        m_networkState = NETWORK_EMPTY;
        scheduleEvent(EventTypeNames::emptied);
    }
    else
        m_networkState = NETWORK_IDLE;

    // 5 - Set the element's delaying-the-load-event flag to false. This stops delaying the load event.
    setShouldDelayLoadEvent(false);

    // 6 - Abort the overall resource selection algorithm.
    m_currentSourceNode = nullptr;

    // Reset m_readyState since m_player is gone.
    m_readyState = HAVE_NOTHING;
    updateMediaController();
    updateActiveTextTrackCues(0);
}

void HTMLMediaElement::clearMediaPlayerAndAudioSourceProviderClient()
{
#if ENABLE(WEB_AUDIO)
    if (m_audioSourceNode)
        m_audioSourceNode->lock();

    if (audioSourceProvider())
        audioSourceProvider()->setClient(0);
#endif

    m_player.clear();

#if ENABLE(WEB_AUDIO)
    if (m_audioSourceNode)
        m_audioSourceNode->unlock();
#endif
}

void HTMLMediaElement::clearMediaPlayer(int flags)
{
    forgetResourceSpecificTracks();

    closeMediaSource();

    m_delayingLoadForPreloadNone = false;

    clearMediaPlayerAndAudioSourceProviderClient();

    stopPeriodicTimers();
    m_loadTimer.stop();

    m_pendingActionFlags &= ~flags;
    m_loadState = WaitingForSource;

    if (m_textTracks)
        configureTextTrackDisplay(AssumeNoVisibleChange);
}

void HTMLMediaElement::stop()
{
    WTF_LOG(Media, "HTMLMediaElement::stop");

    m_active = false;
    userCancelledLoad();

    // Stop the playback without generating events
    m_playing = false;
    setPausedInternal(true);

    if (renderer())
        renderer()->updateFromElement();

    stopPeriodicTimers();
    cancelPendingEventsAndCallbacks();

    m_asyncEventQueue->close();
}

bool HTMLMediaElement::hasPendingActivity() const
{
    return (hasAudio() && isPlaying()) || m_asyncEventQueue->hasPendingEvents();
}

void HTMLMediaElement::contextDestroyed()
{
    if (m_mediaController)
        m_mediaController->clearExecutionContext();
    ActiveDOMObject::contextDestroyed();
}

bool HTMLMediaElement::isFullscreen() const
{
    return FullscreenElementStack::isActiveFullScreenElement(this);
}

void HTMLMediaElement::enterFullscreen()
{
    WTF_LOG(Media, "HTMLMediaElement::enterFullscreen");

    FullscreenElementStack::from(document()).requestFullScreenForElement(this, 0, FullscreenElementStack::ExemptIFrameAllowFullScreenRequirement);
}

void HTMLMediaElement::exitFullscreen()
{
    WTF_LOG(Media, "HTMLMediaElement::exitFullscreen");

    FullscreenElementStack::from(document()).webkitCancelFullScreen();
}

void HTMLMediaElement::didBecomeFullscreenElement()
{
    if (hasMediaControls())
        mediaControls()->enteredFullscreen();
    if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled() && isHTMLVideoElement(*this))
        document().renderView()->compositor()->setCompositingLayersNeedRebuild();
}

void HTMLMediaElement::willStopBeingFullscreenElement()
{
    if (hasMediaControls())
        mediaControls()->exitedFullscreen();
    if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled() && isHTMLVideoElement(*this))
        document().renderView()->compositor()->setCompositingLayersNeedRebuild();
}

blink::WebLayer* HTMLMediaElement::platformLayer() const
{
    return m_webLayer;
}

bool HTMLMediaElement::hasClosedCaptions() const
{
    if (m_textTracks) {
        for (unsigned i = 0; i < m_textTracks->length(); ++i) {
            if (m_textTracks->item(i)->readinessState() == TextTrack::FailedToLoad)
                continue;

            if (m_textTracks->item(i)->kind() == TextTrack::captionsKeyword()
                || m_textTracks->item(i)->kind() == TextTrack::subtitlesKeyword())
                return true;
        }
    }
    return false;
}

bool HTMLMediaElement::closedCaptionsVisible() const
{
    return m_closedCaptionsVisible;
}

void HTMLMediaElement::updateTextTrackDisplay()
{
    WTF_LOG(Media, "HTMLMediaElement::updateTextTrackDisplay");

    if (!hasMediaControls() && !createMediaControls())
        return;

    mediaControls()->updateTextTrackDisplay();
}

void HTMLMediaElement::setClosedCaptionsVisible(bool closedCaptionVisible)
{
    WTF_LOG(Media, "HTMLMediaElement::setClosedCaptionsVisible(%s)", boolString(closedCaptionVisible));

    if (!m_player || !hasClosedCaptions())
        return;

    m_closedCaptionsVisible = closedCaptionVisible;

    m_processingPreferenceChange = true;
    markCaptionAndSubtitleTracksAsUnconfigured();
    m_processingPreferenceChange = false;

    updateTextTrackDisplay();
}

unsigned HTMLMediaElement::webkitAudioDecodedByteCount() const
{
    if (!m_player)
        return 0;
    return m_player->audioDecodedByteCount();
}

unsigned HTMLMediaElement::webkitVideoDecodedByteCount() const
{
    if (!m_player)
        return 0;
    return m_player->videoDecodedByteCount();
}

bool HTMLMediaElement::isURLAttribute(const Attribute& attribute) const
{
    return attribute.name() == srcAttr || HTMLElement::isURLAttribute(attribute);
}

void HTMLMediaElement::setShouldDelayLoadEvent(bool shouldDelay)
{
    if (m_shouldDelayLoadEvent == shouldDelay)
        return;

    WTF_LOG(Media, "HTMLMediaElement::setShouldDelayLoadEvent(%s)", boolString(shouldDelay));

    m_shouldDelayLoadEvent = shouldDelay;
    if (shouldDelay)
        document().incrementLoadEventDelayCount();
    else
        document().decrementLoadEventDelayCount();
}


MediaControls* HTMLMediaElement::mediaControls() const
{
    return toMediaControls(userAgentShadowRoot()->firstChild());
}

bool HTMLMediaElement::hasMediaControls() const
{
    if (ShadowRoot* userAgent = userAgentShadowRoot()) {
        Node* node = userAgent->firstChild();
        ASSERT_WITH_SECURITY_IMPLICATION(!node || node->isMediaControls());
        return node;
    }

    return false;
}

bool HTMLMediaElement::createMediaControls()
{
    if (hasMediaControls())
        return true;

    RefPtr<MediaControls> mediaControls = MediaControls::create(*this);
    if (!mediaControls)
        return false;

    mediaControls->reset();
    if (isFullscreen())
        mediaControls->enteredFullscreen();

    ensureUserAgentShadowRoot().appendChild(mediaControls);

    if (!controls() || !inDocument())
        mediaControls->hide();

    return true;
}

void HTMLMediaElement::configureMediaControls()
{
    if (!controls() || !inDocument()) {
        if (hasMediaControls())
            mediaControls()->hide();
        return;
    }

    if (!hasMediaControls() && !createMediaControls())
        return;

    mediaControls()->reset();
    mediaControls()->show();
}

void HTMLMediaElement::configureTextTrackDisplay(VisibilityChangeAssumption assumption)
{
    ASSERT(m_textTracks);
    WTF_LOG(Media, "HTMLMediaElement::configureTextTrackDisplay");

    if (m_processingPreferenceChange)
        return;

    bool haveVisibleTextTrack = false;
    for (unsigned i = 0; i < m_textTracks->length(); ++i) {
        if (m_textTracks->item(i)->mode() == TextTrack::showingKeyword()) {
            haveVisibleTextTrack = true;
            break;
        }
    }

    if (assumption == AssumeNoVisibleChange
        && m_haveVisibleTextTrack == haveVisibleTextTrack) {
        updateActiveTextTrackCues(currentTime());
        return;
    }
    m_haveVisibleTextTrack = haveVisibleTextTrack;
    m_closedCaptionsVisible = m_haveVisibleTextTrack;

    if (!m_haveVisibleTextTrack && !hasMediaControls())
        return;
    if (!hasMediaControls() && !createMediaControls())
        return;

    mediaControls()->changedClosedCaptionsVisibility();

    updateActiveTextTrackCues(currentTime());
    updateTextTrackDisplay();
}

void HTMLMediaElement::markCaptionAndSubtitleTracksAsUnconfigured()
{
    if (!m_textTracks)
        return;

    // Mark all tracks as not "configured" so that configureTextTracks()
    // will reconsider which tracks to display in light of new user preferences
    // (e.g. default tracks should not be displayed if the user has turned off
    // captions and non-default tracks should be displayed based on language
    // preferences if the user has turned captions on).
    for (unsigned i = 0; i < m_textTracks->length(); ++i) {
        RefPtr<TextTrack> textTrack = m_textTracks->item(i);
        String kind = textTrack->kind();

        if (kind == TextTrack::subtitlesKeyword() || kind == TextTrack::captionsKeyword())
            textTrack->setHasBeenConfigured(false);
    }
    configureTextTracks();
}

bool HTMLMediaElement::willRespondToMouseClickEvents()
{
    return controls();
}

void* HTMLMediaElement::preDispatchEventHandler(Event* event)
{
    if (event && event->type() == EventTypeNames::webkitfullscreenchange)
        configureMediaControls();

    return 0;
}

void HTMLMediaElement::defaultEventHandler(Event* event)
{
    if (event->type() == EventTypeNames::click && willRespondToMouseClickEvents()) {
        togglePlayState();
        event->setDefaultHandled();
        return;
    }
    HTMLElement::defaultEventHandler(event);
}

void HTMLMediaElement::createMediaPlayer()
{
#if ENABLE(WEB_AUDIO)
    if (m_audioSourceNode)
        m_audioSourceNode->lock();
#endif

    if (m_mediaSource)
        closeMediaSource();

    m_player = MediaPlayer::create(this);

#if ENABLE(WEB_AUDIO)
    if (m_audioSourceNode) {
        // When creating the player, make sure its AudioSourceProvider knows about the MediaElementAudioSourceNode.
        if (audioSourceProvider())
            audioSourceProvider()->setClient(m_audioSourceNode);

        m_audioSourceNode->unlock();
    }
#endif
}

#if ENABLE(WEB_AUDIO)
void HTMLMediaElement::setAudioSourceNode(MediaElementAudioSourceNode* sourceNode)
{
    m_audioSourceNode = sourceNode;

    if (m_audioSourceNode)
        m_audioSourceNode->lock();

    if (audioSourceProvider())
        audioSourceProvider()->setClient(m_audioSourceNode);

    if (m_audioSourceNode)
        m_audioSourceNode->unlock();
}

AudioSourceProvider* HTMLMediaElement::audioSourceProvider()
{
    if (m_player)
        return m_player->audioSourceProvider();

    return 0;
}
#endif

const AtomicString& HTMLMediaElement::mediaGroup() const
{
    return fastGetAttribute(mediagroupAttr);
}

void HTMLMediaElement::setMediaGroup(const AtomicString& group)
{
    // When a media element is created with a mediagroup attribute, and when a media element's mediagroup
    // attribute is set, changed, or removed, the user agent must run the following steps:
    // 1. Let m [this] be the media element in question.
    // 2. Let m have no current media controller, if it currently has one.
    setControllerInternal(nullptr);

    // 3. If m's mediagroup attribute is being removed, then abort these steps.
    if (group.isNull() || group.isEmpty())
        return;

    // 4. If there is another media element whose Document is the same as m's Document (even if one or both
    // of these elements are not actually in the Document),
    HashSet<HTMLMediaElement*> elements = documentToElementSetMap().get(&document());
    for (HashSet<HTMLMediaElement*>::iterator i = elements.begin(); i != elements.end(); ++i) {
        if (*i == this)
            continue;

        // and which also has a mediagroup attribute, and whose mediagroup attribute has the same value as
        // the new value of m's mediagroup attribute,
        if ((*i)->mediaGroup() == group) {
            //  then let controller be that media element's current media controller.
            setControllerInternal((*i)->controller());
            return;
        }
    }

    // Otherwise, let controller be a newly created MediaController.
    setControllerInternal(MediaController::create(Node::executionContext()));
}

MediaController* HTMLMediaElement::controller() const
{
    return m_mediaController.get();
}

void HTMLMediaElement::setController(PassRefPtr<MediaController> controller)
{
    // 4.8.10.11.2 Media controllers: controller attribute.
    // On setting, it must first remove the element's mediagroup attribute, if any,
    removeAttribute(mediagroupAttr);
    // and then set the current media controller to the given value.
    setControllerInternal(controller);
}

void HTMLMediaElement::setControllerInternal(PassRefPtr<MediaController> controller)
{
    if (m_mediaController)
        m_mediaController->removeMediaElement(this);

    m_mediaController = controller;

    if (m_mediaController) {
        UseCounter::count(document(), UseCounter::HTMLMediaElementControllerNotNull);
        m_mediaController->addMediaElement(this);
    }
}

void HTMLMediaElement::updateMediaController()
{
    if (m_mediaController)
        m_mediaController->reportControllerState();
}

bool HTMLMediaElement::isBlocked() const
{
    // A media element is a blocked media element if its readyState attribute is in the
    // HAVE_NOTHING state, the HAVE_METADATA state, or the HAVE_CURRENT_DATA state,
    if (m_readyState <= HAVE_CURRENT_DATA)
        return true;

    // or if the element has paused for user interaction.
    return pausedForUserInteraction();
}

bool HTMLMediaElement::isBlockedOnMediaController() const
{
    if (!m_mediaController)
        return false;

    // A media element is blocked on its media controller if the MediaController is a blocked
    // media controller,
    if (m_mediaController->isBlocked())
        return true;

    // or if its media controller position is either before the media resource's earliest possible
    // position relative to the MediaController's timeline or after the end of the media resource
    // relative to the MediaController's timeline.
    double mediaControllerPosition = m_mediaController->currentTime();
    if (mediaControllerPosition < 0 || mediaControllerPosition > duration())
        return true;

    return false;
}

void HTMLMediaElement::prepareMediaFragmentURI()
{
    MediaFragmentURIParser fragmentParser(m_currentSrc);
    double dur = duration();

    double start = fragmentParser.startTime();
    if (start != MediaFragmentURIParser::invalidTimeValue() && start > 0) {
        m_fragmentStartTime = start;
        if (m_fragmentStartTime > dur)
            m_fragmentStartTime = dur;
    } else
        m_fragmentStartTime = MediaPlayer::invalidTime();

    double end = fragmentParser.endTime();
    if (end != MediaFragmentURIParser::invalidTimeValue() && end > 0 && end > m_fragmentStartTime) {
        m_fragmentEndTime = end;
        if (m_fragmentEndTime > dur)
            m_fragmentEndTime = dur;
    } else
        m_fragmentEndTime = MediaPlayer::invalidTime();

    if (m_fragmentStartTime != MediaPlayer::invalidTime() && m_readyState < HAVE_FUTURE_DATA)
        prepareToPlay();
}

void HTMLMediaElement::applyMediaFragmentURI()
{
    if (m_fragmentStartTime != MediaPlayer::invalidTime()) {
        m_sentEndEvent = false;
        UseCounter::count(document(), UseCounter::HTMLMediaElementSeekToFragmentStart);
        seek(m_fragmentStartTime, IGNORE_EXCEPTION);
    }
}

WebMediaPlayer::CORSMode HTMLMediaElement::corsMode() const
{
    const AtomicString& crossOriginMode = fastGetAttribute(crossoriginAttr);
    if (crossOriginMode.isNull())
        return WebMediaPlayer::CORSModeUnspecified;
    if (equalIgnoringCase(crossOriginMode, "use-credentials"))
        return WebMediaPlayer::CORSModeUseCredentials;
    return WebMediaPlayer::CORSModeAnonymous;
}

void HTMLMediaElement::mediaPlayerSetWebLayer(blink::WebLayer* webLayer)
{
    if (webLayer == m_webLayer)
        return;

    // If either of the layers is null we need to enable or disable compositing. This is done by triggering a style recalc.
    if (!m_webLayer || !webLayer)
        scheduleLayerUpdate();

    if (m_webLayer)
        GraphicsLayer::unregisterContentsLayer(m_webLayer);
    m_webLayer = webLayer;
    if (m_webLayer) {
        m_webLayer->setOpaque(m_opaque);
        GraphicsLayer::registerContentsLayer(m_webLayer);
    }
}

void HTMLMediaElement::mediaPlayerSetOpaque(bool opaque)
{
    m_opaque = opaque;
    if (m_webLayer)
        m_webLayer->setOpaque(m_opaque);
}

void HTMLMediaElement::mediaPlayerMediaSourceOpened(blink::WebMediaSource* webMediaSource)
{
    m_mediaSource->setWebMediaSourceAndOpen(adoptPtr(webMediaSource));
}

bool HTMLMediaElement::isInteractiveContent() const
{
    return fastHasAttribute(controlsAttr);
}

}