root/Source/core/frame/FrameView.cpp

DEFINITIONS

1. updateLayerPositionFlags
2. m_disabled
3. m_didScrollTimer
4. create
5. create
6. reset
7. removeFromAXObjectCache
8. resetScrollbars
9. init
10. prepareForDetach
11. detachCustomScrollbars
12. recalculateScrollbarOverlayStyle
13. clear
14. didFirstLayout
15. invalidateRect
16. setFrameRect
17. scheduleAnimation
18. page
19. renderView
20. setCanHaveScrollbars
21. shouldUseCustomScrollbars
22. createScrollbar
23. setContentsSize
24. clampOffsetAtScale
25. adjustViewSize
26. applyOverflowToViewportAndSetRenderer
27. calculateScrollbarModesForLayoutAndSetViewportRenderer
28. updateCompositingLayersAfterStyleChange
29. updateCompositingLayersAfterLayout
30. usesCompositedScrolling
31. layerForScrolling
32. layerForHorizontalScrollbar
33. layerForVerticalScrollbar
34. layerForScrollCorner
35. hasCompositedContent
36. isEnclosedInCompositingLayer
37. layoutRoot
38. forceLayoutParentViewIfNeeded
39. performPreLayoutTasks
40. performLayout
41. scheduleOrPerformPostLayoutTasks
42. layout
43. repaintTree
44. lifecycle
45. gatherDebugLayoutRects
46. embeddedContentBox
47. addWidget
48. removeWidget
49. updateWidgetPositions
50. addWidgetToUpdate
51. setMediaType
52. mediaType
53. adjustMediaTypeForPrinting
54. useSlowRepaints
55. useSlowRepaintsIfNotOverlapped
56. shouldAttemptToScrollUsingFastPath
57. contentsInCompositedLayer
58. setCannotBlitToWindow
59. addSlowRepaintObject
60. removeSlowRepaintObject
61. addViewportConstrainedObject
62. removeViewportConstrainedObject
63. viewportConstrainedVisibleContentRect
64. viewportConstrainedVisibleContentSizeChanged
65. shouldPlaceVerticalScrollbarOnLeft
66. scrollOffsetForFixedPosition
67. lastKnownMousePosition
68. shouldSetCursor
69. scrollContentsIfNeededRecursive
70. scrollContentsIfNeeded
71. scrollContentsFastPath
72. scrollContentsSlowPath
73. setIsOverlapped
74. setContentIsOpaque
75. restoreScrollbar
76. scrollToFragment
77. scrollToAnchor
78. maintainScrollPositionAtAnchor
79. scrollElementToRect
80. setScrollPosition
81. setScrollPositionNonProgrammatically
82. layoutSize
83. setLayoutSize
84. scrollPositionChanged
85. didScrollTimerFired
86. updateLayersAndCompositingAfterScrollIfNeeded
87. updateFixedElementRepaintRectsAfterScroll
88. shouldRubberBandInDirection
89. isRubberBandInProgress
90. hostWindow
91. repaintContentRectangle
92. contentsResized
93. scrollbarExistenceDidChange
94. handleLoadCompleted
95. scheduleRelayout
96. isObjectAncestorContainerOf
97. scheduleRelayoutOfSubtree
98. layoutPending
99. isInPerformLayout
100. needsLayout
101. setNeedsLayout
102. isTransparent
103. setTransparent
104. hasOpaqueBackground
105. baseBackgroundColor
106. setBaseBackgroundColor
107. updateBackgroundRecursively
108. scrollToAnchor
109. updateWidgets
110. updateWidgetsTimerFired
111. flushAnyPendingPostLayoutTasks
112. scheduleUpdateWidgetsIfNecessary
113. performPostLayoutTasks
114. sendResizeEventIfNeeded
115. postLayoutTimerFired
116. updateCounters
117. autoSizeIfEnabled
118. updateOverflowStatus
119. windowClipRect
120. windowClipRectForFrameOwner
121. isActive
122. scrollTo
123. invalidateScrollbarRect
124. getTickmarks
125. windowResizerRect
126. setVisibleContentScaleFactor
127. setInputEventsTransformForEmulation
128. inputEventsOffsetForEmulation
129. inputEventsScaleFactor
130. scrollbarsCanBeActive
131. scrollableAreaBoundingBox
132. isScrollable
133. updateScrollableAreaSet
134. shouldSuspendScrollAnimations
135. scrollbarStyleChanged
136. notifyPageThatContentAreaWillPaint
137. scrollAnimatorEnabled
138. updateAnnotatedRegions
139. updateScrollCorner
140. paintScrollCorner
141. paintScrollbar
142. documentBackgroundColor
143. hasCustomScrollbars
144. parentFrameView
145. updateControlTints
146. wasScrolledByUser
147. setWasScrolledByUser
148. paintContents
149. setPaintBehavior
150. paintBehavior
151. isPainting
152. setNodeToDraw
153. paintOverhangAreas
154. updateLayoutAndStyleForPainting
155. updateLayoutAndStyleIfNeededRecursive
156. enableAutoSizeMode
157. forceLayout
158. forceLayoutForPagination
159. convertFromRenderer
160. convertToRenderer
161. convertFromRenderer
162. convertToRenderer
163. convertToContainingView
164. convertFromContainingView
165. convertToContainingView
166. convertFromContainingView
167. setTracksRepaints
168. resetTrackedRepaints
169. trackedRepaintRectsAsText
170. addResizerArea
171. removeResizerArea
172. addScrollableArea
173. removeScrollableArea
174. containsScrollableArea
175. removeChild
176. wheelEvent
177. isVerticalDocument
178. isFlippedDocument
179. axObjectCache
180. setCursor
181. isMainFrame
182. frameRectsChanged
183. setLayoutSizeInternal
184. didAddScrollbar
185. willRemoveScrollbar

/*
 * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
 *                     1999 Lars Knoll <knoll@kde.org>
 *                     1999 Antti Koivisto <koivisto@kde.org>
 *                     2000 Dirk Mueller <mueller@kde.org>
 * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
 *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
 * Copyright (C) 2009 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "core/frame/FrameView.h"

#include "HTMLNames.h"
#include "RuntimeEnabledFeatures.h"
#include "core/accessibility/AXObjectCache.h"
#include "core/css/FontFaceSet.h"
#include "core/css/resolver/StyleResolver.h"
#include "core/dom/DocumentMarkerController.h"
#include "core/editing/FrameSelection.h"
#include "core/events/OverflowEvent.h"
#include "core/fetch/ResourceFetcher.h"
#include "core/fetch/ResourceLoadPriorityOptimizer.h"
#include "core/frame/LocalFrame.h"
#include "core/frame/Settings.h"
#include "core/html/HTMLFrameElement.h"
#include "core/html/HTMLPlugInElement.h"
#include "core/html/parser/TextResourceDecoder.h"
#include "core/inspector/InspectorInstrumentation.h"
#include "core/loader/FrameLoader.h"
#include "core/loader/FrameLoaderClient.h"
#include "core/page/Chrome.h"
#include "core/page/ChromeClient.h"
#include "core/page/EventHandler.h"
#include "core/page/FocusController.h"
#include "core/page/FrameTree.h"
#include "core/page/scrolling/ScrollingCoordinator.h"
#include "core/rendering/FastTextAutosizer.h"
#include "core/rendering/RenderCounter.h"
#include "core/rendering/RenderEmbeddedObject.h"
#include "core/rendering/RenderLayer.h"
#include "core/rendering/RenderListBox.h"
#include "core/rendering/RenderPart.h"
#include "core/rendering/RenderScrollbar.h"
#include "core/rendering/RenderScrollbarPart.h"
#include "core/rendering/RenderTheme.h"
#include "core/rendering/RenderView.h"
#include "core/rendering/RenderWidget.h"
#include "core/rendering/TextAutosizer.h"
#include "core/rendering/compositing/CompositedLayerMapping.h"
#include "core/rendering/compositing/RenderLayerCompositor.h"
#include "core/rendering/style/RenderStyle.h"
#include "core/rendering/svg/RenderSVGRoot.h"
#include "core/svg/SVGDocument.h"
#include "core/svg/SVGSVGElement.h"
#include "platform/TraceEvent.h"
#include "platform/fonts/FontCache.h"
#include "platform/geometry/FloatRect.h"
#include "platform/graphics/GraphicsContext.h"
#include "platform/graphics/GraphicsLayerDebugInfo.h"
#include "platform/scroll/ScrollAnimator.h"
#include "platform/scroll/ScrollbarTheme.h"
#include "platform/text/TextStream.h"
#include "wtf/CurrentTime.h"
#include "wtf/TemporaryChange.h"

namespace WebCore {

using namespace HTMLNames;

double FrameView::s_currentFrameTimeStamp = 0.0;
bool FrameView::s_inPaintContents = false;

// The maximum number of updateWidgets iterations that should be done before returning.
static const unsigned maxUpdateWidgetsIterations = 2;
static const double resourcePriorityUpdateDelayAfterScroll = 0.250;

static RenderLayer::UpdateLayerPositionsFlags updateLayerPositionFlags(RenderLayer* layer, bool isRelayoutingSubtree, bool didFullRepaint)
{
    RenderLayer::UpdateLayerPositionsFlags flags = didFullRepaint ? RenderLayer::NeedsFullRepaintInBacking : RenderLayer::CheckForRepaint;

    if (isRelayoutingSubtree && layer->isPaginated())
        flags |= RenderLayer::UpdatePagination;

    return flags;
}

class FrameViewLayoutStateMaintainer {
    WTF_MAKE_NONCOPYABLE(FrameViewLayoutStateMaintainer);
public:
    FrameViewLayoutStateMaintainer(RenderObject& root, bool inSubtreeLayout)
        : m_view(*root.view())
        , m_inSubtreeLayout(inSubtreeLayout)
        , m_disabled(inSubtreeLayout && m_view.shouldDisableLayoutStateForSubtree(root))
    {
        if (m_inSubtreeLayout)
            m_view.pushLayoutState(root);
        if (m_disabled)
            m_view.disableLayoutState();
    }

    ~FrameViewLayoutStateMaintainer()
    {
        if (m_disabled)
            m_view.enableLayoutState();
        if (m_inSubtreeLayout)
            m_view.popLayoutState();
    }
private:
    RenderView& m_view;
    bool m_inSubtreeLayout;
    bool m_disabled;
};

FrameView::FrameView(LocalFrame* frame)
    : m_frame(frame)
    , m_canHaveScrollbars(true)
    , m_slowRepaintObjectCount(0)
    , m_hasPendingLayout(false)
    , m_layoutSubtreeRoot(0)
    , m_inSynchronousPostLayout(false)
    , m_postLayoutTasksTimer(this, &FrameView::postLayoutTimerFired)
    , m_updateWidgetsTimer(this, &FrameView::updateWidgetsTimerFired)
    , m_isTransparent(false)
    , m_baseBackgroundColor(Color::white)
    , m_mediaType("screen")
    , m_overflowStatusDirty(true)
    , m_viewportRenderer(0)
    , m_wasScrolledByUser(false)
    , m_inProgrammaticScroll(false)
    , m_safeToPropagateScrollToParent(true)
    , m_isTrackingRepaints(false)
    , m_scrollCorner(0)
    , m_shouldAutoSize(false)
    , m_inAutoSize(false)
    , m_didRunAutosize(false)
    , m_hasSoftwareFilters(false)
    , m_visibleContentScaleFactor(1)
    , m_inputEventsScaleFactorForEmulation(1)
    , m_layoutSizeFixedToFrameSize(true)
    , m_didScrollTimer(this, &FrameView::didScrollTimerFired)
{
    ASSERT(m_frame);
    init();

    if (!isMainFrame())
        return;

    ScrollableArea::setVerticalScrollElasticity(ScrollElasticityAllowed);
    ScrollableArea::setHorizontalScrollElasticity(ScrollElasticityAllowed);
}

PassRefPtr<FrameView> FrameView::create(LocalFrame* frame)
{
    RefPtr<FrameView> view = adoptRef(new FrameView(frame));
    view->show();
    return view.release();
}

PassRefPtr<FrameView> FrameView::create(LocalFrame* frame, const IntSize& initialSize)
{
    RefPtr<FrameView> view = adoptRef(new FrameView(frame));
    view->Widget::setFrameRect(IntRect(view->location(), initialSize));
    view->setLayoutSizeInternal(initialSize);

    view->show();
    return view.release();
}

FrameView::~FrameView()
{
    if (m_postLayoutTasksTimer.isActive())
        m_postLayoutTasksTimer.stop();

    if (m_didScrollTimer.isActive())
        m_didScrollTimer.stop();

    removeFromAXObjectCache();
    resetScrollbars();

    // Custom scrollbars should already be destroyed at this point
    ASSERT(!horizontalScrollbar() || !horizontalScrollbar()->isCustomScrollbar());
    ASSERT(!verticalScrollbar() || !verticalScrollbar()->isCustomScrollbar());

    setHasHorizontalScrollbar(false); // Remove native scrollbars now before we lose the connection to the HostWindow.
    setHasVerticalScrollbar(false);

    ASSERT(!m_scrollCorner);

    ASSERT(m_frame);
    ASSERT(m_frame->view() != this || !m_frame->contentRenderer());
    HTMLFrameOwnerElement* ownerElement = m_frame->ownerElement();
    if (ownerElement && ownerElement->ownedWidget() == this)
        ownerElement->setWidget(nullptr);
}

void FrameView::reset()
{
    m_cannotBlitToWindow = false;
    m_isOverlapped = false;
    m_contentIsOpaque = false;
    m_hasPendingLayout = false;
    m_layoutSubtreeRoot = 0;
    m_doFullRepaint = false;
    m_layoutSchedulingEnabled = true;
    m_inPerformLayout = false;
    m_canRepaintDuringPerformLayout = false;
    m_doingPreLayoutStyleUpdate = false;
    m_inSynchronousPostLayout = false;
    m_layoutCount = 0;
    m_nestedLayoutCount = 0;
    m_postLayoutTasksTimer.stop();
    m_updateWidgetsTimer.stop();
    m_firstLayout = true;
    m_firstLayoutCallbackPending = false;
    m_wasScrolledByUser = false;
    m_safeToPropagateScrollToParent = true;
    m_lastViewportSize = IntSize();
    m_lastZoomFactor = 1.0f;
    m_isTrackingRepaints = false;
    m_trackedRepaintRects.clear();
    m_lastPaintTime = 0;
    m_paintBehavior = PaintBehaviorNormal;
    m_isPainting = false;
    m_visuallyNonEmptyCharacterCount = 0;
    m_visuallyNonEmptyPixelCount = 0;
    m_isVisuallyNonEmpty = false;
    m_firstVisuallyNonEmptyLayoutCallbackPending = true;
    m_maintainScrollPositionAnchor = nullptr;
    m_viewportConstrainedObjects.clear();
}

void FrameView::removeFromAXObjectCache()
{
    if (AXObjectCache* cache = axObjectCache())
        cache->remove(this);
}

void FrameView::resetScrollbars()
{
    // Reset the document's scrollbars back to our defaults before we yield the floor.
    m_firstLayout = true;
    setScrollbarsSuppressed(true);
    if (m_canHaveScrollbars)
        setScrollbarModes(ScrollbarAuto, ScrollbarAuto);
    else
        setScrollbarModes(ScrollbarAlwaysOff, ScrollbarAlwaysOff);
    setScrollbarsSuppressed(false);
}

void FrameView::init()
{
    reset();

    m_size = LayoutSize();

    // Propagate the marginwidth/height and scrolling modes to the view.
    Element* ownerElement = m_frame->ownerElement();
    if (ownerElement && (isHTMLFrameElement(*ownerElement) || isHTMLIFrameElement(*ownerElement))) {
        HTMLFrameElementBase* frameElt = toHTMLFrameElementBase(ownerElement);
        if (frameElt->scrollingMode() == ScrollbarAlwaysOff)
            setCanHaveScrollbars(false);
    }
}

void FrameView::prepareForDetach()
{
    RELEASE_ASSERT(!isInPerformLayout());

    if (ScrollAnimator* scrollAnimator = existingScrollAnimator())
        scrollAnimator->cancelAnimations();

    detachCustomScrollbars();
    // When the view is no longer associated with a frame, it needs to be removed from the ax object cache
    // right now, otherwise it won't be able to reach the topDocument()'s axObject cache later.
    removeFromAXObjectCache();

    if (m_frame->page()) {
        if (ScrollingCoordinator* scrollingCoordinator = m_frame->page()->scrollingCoordinator())
            scrollingCoordinator->willDestroyScrollableArea(this);
    }
}

void FrameView::detachCustomScrollbars()
{
    Scrollbar* horizontalBar = horizontalScrollbar();
    if (horizontalBar && horizontalBar->isCustomScrollbar())
        setHasHorizontalScrollbar(false);

    Scrollbar* verticalBar = verticalScrollbar();
    if (verticalBar && verticalBar->isCustomScrollbar())
        setHasVerticalScrollbar(false);

    if (m_scrollCorner) {
        m_scrollCorner->destroy();
        m_scrollCorner = 0;
    }
}

void FrameView::recalculateScrollbarOverlayStyle()
{
    ScrollbarOverlayStyle oldOverlayStyle = scrollbarOverlayStyle();
    ScrollbarOverlayStyle overlayStyle = ScrollbarOverlayStyleDefault;

    Color backgroundColor = documentBackgroundColor();
    // Reduce the background color from RGB to a lightness value
    // and determine which scrollbar style to use based on a lightness
    // heuristic.
    double hue, saturation, lightness;
    backgroundColor.getHSL(hue, saturation, lightness);
    if (lightness <= .5)
        overlayStyle = ScrollbarOverlayStyleLight;

    if (oldOverlayStyle != overlayStyle)
        setScrollbarOverlayStyle(overlayStyle);
}

void FrameView::clear()
{
    reset();
    setScrollbarsSuppressed(true);
}

bool FrameView::didFirstLayout() const
{
    return !m_firstLayout;
}

void FrameView::invalidateRect(const IntRect& rect)
{
    if (!parent()) {
        if (HostWindow* window = hostWindow())
            window->invalidateContentsAndRootView(rect);
        return;
    }

    RenderPart* renderer = m_frame->ownerRenderer();
    if (!renderer)
        return;

    IntRect repaintRect = rect;
    repaintRect.move(renderer->borderLeft() + renderer->paddingLeft(),
                     renderer->borderTop() + renderer->paddingTop());
    renderer->repaintRectangle(repaintRect);
}

void FrameView::setFrameRect(const IntRect& newRect)
{
    IntRect oldRect = frameRect();
    if (newRect == oldRect)
        return;

    // Autosized font sizes depend on the width of the viewing area.
    bool autosizerNeedsUpdating = false;
    if (newRect.width() != oldRect.width()) {
        if (isMainFrame() && m_frame->settings()->textAutosizingEnabled()) {
            autosizerNeedsUpdating = true;
            for (LocalFrame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext()) {
                if (TextAutosizer* textAutosizer = frame->document()->textAutosizer())
                    textAutosizer->recalculateMultipliers();
            }
        }
    }

    ScrollView::setFrameRect(newRect);

    updateScrollableAreaSet();

    if (autosizerNeedsUpdating) {
        // This needs to be after the call to ScrollView::setFrameRect, because it reads the new width.
        if (FastTextAutosizer* textAutosizer = m_frame->document()->fastTextAutosizer())
            textAutosizer->updatePageInfoInAllFrames();
    }

    if (RenderView* renderView = this->renderView()) {
        if (renderView->usesCompositing())
            renderView->compositor()->frameViewDidChangeSize();
    }

    viewportConstrainedVisibleContentSizeChanged(newRect.width() != oldRect.width(), newRect.height() != oldRect.height());
}

bool FrameView::scheduleAnimation()
{
    if (HostWindow* window = hostWindow()) {
        window->scheduleAnimation();
        return true;
    }
    return false;
}

Page* FrameView::page() const
{
    return frame().page();
}

RenderView* FrameView::renderView() const
{
    return frame().contentRenderer();
}

void FrameView::setCanHaveScrollbars(bool canHaveScrollbars)
{
    m_canHaveScrollbars = canHaveScrollbars;
    ScrollView::setCanHaveScrollbars(canHaveScrollbars);
}

bool FrameView::shouldUseCustomScrollbars(Element*& customScrollbarElement, LocalFrame*& customScrollbarFrame)
{
    customScrollbarElement = 0;
    customScrollbarFrame = 0;

    if (Settings* settings = m_frame->settings()) {
        if (!settings->allowCustomScrollbarInMainFrame() && isMainFrame())
            return false;
    }

    // FIXME: We need to update the scrollbar dynamically as documents change (or as doc elements and bodies get discovered that have custom styles).
    Document* doc = m_frame->document();

    // Try the <body> element first as a scrollbar source.
    Element* body = doc ? doc->body() : 0;
    if (body && body->renderer() && body->renderer()->style()->hasPseudoStyle(SCROLLBAR)) {
        customScrollbarElement = body;
        return true;
    }

    // If the <body> didn't have a custom style, then the root element might.
    Element* docElement = doc ? doc->documentElement() : 0;
    if (docElement && docElement->renderer() && docElement->renderer()->style()->hasPseudoStyle(SCROLLBAR)) {
        customScrollbarElement = docElement;
        return true;
    }

    // If we have an owning ipage/LocalFrame element, then it can set the custom scrollbar also.
    RenderPart* frameRenderer = m_frame->ownerRenderer();
    if (frameRenderer && frameRenderer->style()->hasPseudoStyle(SCROLLBAR)) {
        customScrollbarFrame = m_frame.get();
        return true;
    }

    return false;
}

PassRefPtr<Scrollbar> FrameView::createScrollbar(ScrollbarOrientation orientation)
{
    Element* customScrollbarElement = 0;
    LocalFrame* customScrollbarFrame = 0;
    if (shouldUseCustomScrollbars(customScrollbarElement, customScrollbarFrame))
        return RenderScrollbar::createCustomScrollbar(this, orientation, customScrollbarElement, customScrollbarFrame);

    // Nobody set a custom style, so we just use a native scrollbar.
    return ScrollView::createScrollbar(orientation);
}

void FrameView::setContentsSize(const IntSize& size)
{
    if (size == contentsSize())
        return;

    ScrollView::setContentsSize(size);
    ScrollView::contentsResized();

    Page* page = frame().page();
    if (!page)
        return;

    updateScrollableAreaSet();

    page->chrome().contentsSizeChanged(m_frame.get(), size);
}

IntPoint FrameView::clampOffsetAtScale(const IntPoint& offset, float scale) const
{
    IntPoint maxScrollExtent(contentsSize().width() - scrollOrigin().x(), contentsSize().height() - scrollOrigin().y());
    FloatSize scaledSize = unscaledVisibleContentSize();
    if (scale)
        scaledSize.scale(1 / scale);

    IntPoint clampedOffset = offset;
    clampedOffset = clampedOffset.shrunkTo(maxScrollExtent - expandedIntSize(scaledSize));
    clampedOffset = clampedOffset.expandedTo(-scrollOrigin());

    return clampedOffset;
}

void FrameView::adjustViewSize()
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return;

    ASSERT(m_frame->view() == this);

    const IntRect rect = renderView->documentRect();
    const IntSize& size = rect.size();
    ScrollView::setScrollOrigin(IntPoint(-rect.x(), -rect.y()), !m_frame->document()->printing(), size == contentsSize());

    setContentsSize(size);
}

void FrameView::applyOverflowToViewportAndSetRenderer(RenderObject* o, ScrollbarMode& hMode, ScrollbarMode& vMode)
{
    // Handle the overflow:hidden/scroll case for the body/html elements.  WinIE treats
    // overflow:hidden and overflow:scroll on <body> as applying to the document's
    // scrollbars.  The CSS2.1 draft states that HTML UAs should use the <html> or <body> element and XML/XHTML UAs should
    // use the root element.

    EOverflow overflowX = o->style()->overflowX();
    EOverflow overflowY = o->style()->overflowY();

    if (o->isSVGRoot()) {
        // overflow is ignored in stand-alone SVG documents.
        if (!toRenderSVGRoot(o)->isEmbeddedThroughFrameContainingSVGDocument())
            return;
        overflowX = OHIDDEN;
        overflowY = OHIDDEN;
    }

    bool ignoreOverflowHidden = false;
    if (m_frame->settings()->ignoreMainFrameOverflowHiddenQuirk() && m_frame->isMainFrame())
        ignoreOverflowHidden = true;

    switch (overflowX) {
        case OHIDDEN:
            if (!ignoreOverflowHidden)
                hMode = ScrollbarAlwaysOff;
            break;
        case OSCROLL:
            hMode = ScrollbarAlwaysOn;
            break;
        case OAUTO:
            hMode = ScrollbarAuto;
            break;
        default:
            // Don't set it at all.
            ;
    }

     switch (overflowY) {
        case OHIDDEN:
            if (!ignoreOverflowHidden)
                vMode = ScrollbarAlwaysOff;
            break;
        case OSCROLL:
            vMode = ScrollbarAlwaysOn;
            break;
        case OAUTO:
            vMode = ScrollbarAuto;
            break;
        default:
            // Don't set it at all.
            ;
    }

    m_viewportRenderer = o;
}

void FrameView::calculateScrollbarModesForLayoutAndSetViewportRenderer(ScrollbarMode& hMode, ScrollbarMode& vMode, ScrollbarModesCalculationStrategy strategy)
{
    m_viewportRenderer = 0;

    const HTMLFrameOwnerElement* owner = m_frame->ownerElement();
    if (owner && (owner->scrollingMode() == ScrollbarAlwaysOff)) {
        hMode = ScrollbarAlwaysOff;
        vMode = ScrollbarAlwaysOff;
        return;
    }

    if (m_canHaveScrollbars || strategy == RulesFromWebContentOnly) {
        hMode = ScrollbarAuto;
        vMode = ScrollbarAuto;
    } else {
        hMode = ScrollbarAlwaysOff;
        vMode = ScrollbarAlwaysOff;
    }

    if (!isSubtreeLayout()) {
        Document* document = m_frame->document();
        Node* body = document->body();
        if (isHTMLFrameSetElement(body) && body->renderer()) {
            vMode = ScrollbarAlwaysOff;
            hMode = ScrollbarAlwaysOff;
        } else if (Element* viewportElement = document->viewportDefiningElement()) {
            if (RenderObject* viewportRenderer = viewportElement->renderer()) {
                if (viewportRenderer->style())
                    applyOverflowToViewportAndSetRenderer(viewportRenderer, hMode, vMode);
            }
        }
    }
}

void FrameView::updateCompositingLayersAfterStyleChange()
{
    TRACE_EVENT0("webkit", "FrameView::updateCompositingLayersAfterStyleChange");
    RenderView* renderView = this->renderView();
    if (!renderView)
        return;

    // If we expect to update compositing after an incipient layout, don't do so here.
    if (m_doingPreLayoutStyleUpdate || layoutPending() || renderView->needsLayout())
        return;

    // FIXME: Remove incremental compositing updates after fixing the chicken/egg issues
    // https://code.google.com/p/chromium/issues/detail?id=343756
    DisableCompositingQueryAsserts disabler;

    // This call will make sure the cached hasAcceleratedCompositing is updated from the pref
    renderView->compositor()->cacheAcceleratedCompositingFlags();

    // Sometimes we will change a property (for example, z-index) that will not
    // cause a layout, but will require us to update compositing state. We only
    // need to do this if a layout is not already scheduled.
    if (!needsLayout())
        renderView->compositor()->updateCompositingRequirementsState();

    renderView->compositor()->setNeedsCompositingUpdate(CompositingUpdateAfterStyleChange);
}

void FrameView::updateCompositingLayersAfterLayout()
{
    TRACE_EVENT0("webkit", "FrameView::updateCompositingLayersAfterLayout");
    RenderView* renderView = this->renderView();
    if (!renderView)
        return;

    // FIXME: Remove incremental compositing updates after fixing the chicken/egg issues
    // https://code.google.com/p/chromium/issues/detail?id=343756
    DisableCompositingQueryAsserts disabler;

    // This call will make sure the cached hasAcceleratedCompositing is updated from the pref
    renderView->compositor()->cacheAcceleratedCompositingFlags();
    renderView->compositor()->updateCompositingRequirementsState();
    renderView->compositor()->setNeedsCompositingUpdate(CompositingUpdateAfterLayout);
}

bool FrameView::usesCompositedScrolling() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return false;
    if (m_frame->settings() && m_frame->settings()->compositedScrollingForFramesEnabled())
        return renderView->compositor()->inForcedCompositingMode();
    return false;
}

GraphicsLayer* FrameView::layerForScrolling() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;
    return renderView->compositor()->scrollLayer();
}

GraphicsLayer* FrameView::layerForHorizontalScrollbar() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;
    return renderView->compositor()->layerForHorizontalScrollbar();
}

GraphicsLayer* FrameView::layerForVerticalScrollbar() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;
    return renderView->compositor()->layerForVerticalScrollbar();
}

GraphicsLayer* FrameView::layerForScrollCorner() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;
    return renderView->compositor()->layerForScrollCorner();
}

bool FrameView::hasCompositedContent() const
{
    if (RenderView* renderView = this->renderView())
        return renderView->compositor()->inCompositingMode();
    return false;
}

bool FrameView::isEnclosedInCompositingLayer() const
{
    RenderObject* frameOwnerRenderer = m_frame->ownerRenderer();
    if (frameOwnerRenderer && frameOwnerRenderer->containerForRepaint())
        return true;

    if (FrameView* parentView = parentFrameView())
        return parentView->isEnclosedInCompositingLayer();

    return false;
}

RenderObject* FrameView::layoutRoot(bool onlyDuringLayout) const
{
    return onlyDuringLayout && layoutPending() ? 0 : m_layoutSubtreeRoot;
}

inline void FrameView::forceLayoutParentViewIfNeeded()
{
    RenderPart* ownerRenderer = m_frame->ownerRenderer();
    if (!ownerRenderer || !ownerRenderer->frame())
        return;

    RenderBox* contentBox = embeddedContentBox();
    if (!contentBox)
        return;

    RenderSVGRoot* svgRoot = toRenderSVGRoot(contentBox);
    if (svgRoot->everHadLayout() && !svgRoot->needsLayout())
        return;

    // If the embedded SVG document appears the first time, the ownerRenderer has already finished
    // layout without knowing about the existence of the embedded SVG document, because RenderReplaced
    // embeddedContentBox() returns 0, as long as the embedded document isn't loaded yet. Before
    // bothering to lay out the SVG document, mark the ownerRenderer needing layout and ask its
    // FrameView for a layout. After that the RenderEmbeddedObject (ownerRenderer) carries the
    // correct size, which RenderSVGRoot::computeReplacedLogicalWidth/Height rely on, when laying
    // out for the first time, or when the RenderSVGRoot size has changed dynamically (eg. via <script>).
    RefPtr<FrameView> frameView = ownerRenderer->frame()->view();

    // Mark the owner renderer as needing layout.
    ownerRenderer->setNeedsLayoutAndPrefWidthsRecalc();

    // Synchronously enter layout, to layout the view containing the host object/embed/iframe.
    ASSERT(frameView);
    frameView->layout();
}

void FrameView::performPreLayoutTasks()
{
    TRACE_EVENT0("webkit", "FrameView::performPreLayoutTasks");
    lifecycle().advanceTo(DocumentLifecycle::InPreLayout);

    // Don't schedule more layouts, we're in one.
    TemporaryChange<bool> changeSchedulingEnabled(m_layoutSchedulingEnabled, false);

    if (!m_nestedLayoutCount && !m_inSynchronousPostLayout && m_postLayoutTasksTimer.isActive()) {
        // This is a new top-level layout. If there are any remaining tasks from the previous layout, finish them now.
        m_inSynchronousPostLayout = true;
        performPostLayoutTasks();
        m_inSynchronousPostLayout = false;
    }

    Document* document = m_frame->document();
    document->notifyResizeForViewportUnits();

    // Viewport-dependent media queries may cause us to need completely different style information.
    if (!document->styleResolver() || document->styleResolver()->mediaQueryAffectedByViewportChange()) {
        document->styleResolverChanged(RecalcStyleDeferred);
        document->mediaQueryAffectingValueChanged();

        // FIXME: This instrumentation event is not strictly accurate since cached media query results
        //        do not persist across StyleResolver rebuilds.
        InspectorInstrumentation::mediaQueryResultChanged(document);
    } else {
        document->evaluateMediaQueryList();
    }

    // Always ensure our style info is up-to-date. This can happen in situations where
    // the layout beats any sort of style recalc update that needs to occur.
    TemporaryChange<bool> changeDoingPreLayoutStyleUpdate(m_doingPreLayoutStyleUpdate, true);
    document->updateRenderTreeIfNeeded();
    lifecycle().advanceTo(DocumentLifecycle::StyleClean);
}

void FrameView::performLayout(RenderObject* rootForThisLayout, bool inSubtreeLayout)
{
    TRACE_EVENT0("webkit", "FrameView::performLayout");

    ASSERT(!isInPerformLayout());
    lifecycle().advanceTo(DocumentLifecycle::InPerformLayout);

    TemporaryChange<bool> changeInPerformLayout(m_inPerformLayout, true);

    // performLayout is the actual guts of layout().
    // FIXME: The 300 other lines in layout() probably belong in other helper functions
    // so that a single human could understand what layout() is actually doing.

    FrameViewLayoutStateMaintainer statePusher(*rootForThisLayout, inSubtreeLayout);
    forceLayoutParentViewIfNeeded();

    // FIXME (crbug.com/256657): Do not do two layouts for text autosizing.
    rootForThisLayout->layout();
    gatherDebugLayoutRects(rootForThisLayout);

    ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->updateAllImageResourcePriorities();

    TextAutosizer* textAutosizer = frame().document()->textAutosizer();
    bool autosized = textAutosizer && textAutosizer->processSubtree(rootForThisLayout);
    if (autosized && rootForThisLayout->needsLayout()) {
        TRACE_EVENT0("webkit", "2nd layout due to Text Autosizing");
        UseCounter::count(*frame().document(), UseCounter::TextAutosizingLayout);
        rootForThisLayout->layout();
        gatherDebugLayoutRects(rootForThisLayout);
    }

    lifecycle().advanceTo(DocumentLifecycle::AfterPerformLayout);
}

void FrameView::scheduleOrPerformPostLayoutTasks()
{
    if (m_postLayoutTasksTimer.isActive())
        return;

    if (!m_inSynchronousPostLayout) {
        m_inSynchronousPostLayout = true;
        // Calls resumeScheduledEvents()
        performPostLayoutTasks();
        m_inSynchronousPostLayout = false;
    }

    if (!m_postLayoutTasksTimer.isActive() && (needsLayout() || m_inSynchronousPostLayout)) {
        // If we need layout or are already in a synchronous call to postLayoutTasks(),
        // defer widget updates and event dispatch until after we return. postLayoutTasks()
        // can make us need to update again, and we can get stuck in a nasty cycle unless
        // we call it through the timer here.
        m_postLayoutTasksTimer.startOneShot(0, FROM_HERE);
        if (needsLayout())
            layout();
    }
}

void FrameView::layout(bool allowSubtree)
{
    // We should never layout a Document which is not in a LocalFrame.
    ASSERT(m_frame);
    ASSERT(m_frame->view() == this);
    ASSERT(m_frame->page());

    if (isInPerformLayout() || !m_frame->document()->isActive())
        return;

    TRACE_EVENT0("webkit", "FrameView::layout");
    TRACE_EVENT_SCOPED_SAMPLING_STATE("Blink", "Layout");

    // Protect the view from being deleted during layout (in recalcStyle)
    RefPtr<FrameView> protector(this);

    // Every scroll that happens during layout is programmatic.
    TemporaryChange<bool> changeInProgrammaticScroll(m_inProgrammaticScroll, true);

    m_hasPendingLayout = false;
    DocumentLifecycle::Scope lifecycleScope(lifecycle(), DocumentLifecycle::LayoutClean);

    RELEASE_ASSERT(!isPainting());

    InspectorInstrumentationCookie cookie = InspectorInstrumentation::willLayout(m_frame.get());

    if (!allowSubtree && isSubtreeLayout()) {
        m_layoutSubtreeRoot->markContainingBlocksForLayout(false);
        m_layoutSubtreeRoot = 0;
    }

    performPreLayoutTasks();

    // If there is only one ref to this view left, then its going to be destroyed as soon as we exit,
    // so there's no point to continuing to layout
    if (protector->hasOneRef())
        return;

    Document* document = m_frame->document();
    bool inSubtreeLayout = isSubtreeLayout();
    RenderObject* rootForThisLayout = inSubtreeLayout ? m_layoutSubtreeRoot : document->renderer();
    if (!rootForThisLayout) {
        // FIXME: Do we need to set m_size here?
        ASSERT_NOT_REACHED();
        return;
    }

    FontCachePurgePreventer fontCachePurgePreventer;
    RenderLayer* layer;
    {
        TemporaryChange<bool> changeSchedulingEnabled(m_layoutSchedulingEnabled, false);

        m_nestedLayoutCount++;
        if (!inSubtreeLayout) {
            Document* document = m_frame->document();
            Node* body = document->body();
            if (body && body->renderer()) {
                if (isHTMLFrameSetElement(*body)) {
                    body->renderer()->setChildNeedsLayout();
                } else if (isHTMLBodyElement(*body)) {
                    if (!m_firstLayout && m_size.height() != layoutSize().height() && body->renderer()->enclosingBox()->stretchesToViewport())
                        body->renderer()->setChildNeedsLayout();
                }
            }
        }
        updateCounters();
        autoSizeIfEnabled();

        ScrollbarMode hMode;
        ScrollbarMode vMode;
        calculateScrollbarModesForLayoutAndSetViewportRenderer(hMode, vMode);

        bool shouldDoFullRepaint = !inSubtreeLayout && (m_firstLayout || toRenderView(rootForThisLayout)->document().printing());

        if (!inSubtreeLayout) {
            // Now set our scrollbar state for the layout.
            ScrollbarMode currentHMode = horizontalScrollbarMode();
            ScrollbarMode currentVMode = verticalScrollbarMode();

            if (m_firstLayout) {
                setScrollbarsSuppressed(true);

                m_firstLayout = false;
                m_firstLayoutCallbackPending = true;
                m_lastViewportSize = layoutSize(IncludeScrollbars);
                m_lastZoomFactor = rootForThisLayout->style()->zoom();

                // Set the initial vMode to AlwaysOn if we're auto.
                if (vMode == ScrollbarAuto)
                    setVerticalScrollbarMode(ScrollbarAlwaysOn); // This causes a vertical scrollbar to appear.
                // Set the initial hMode to AlwaysOff if we're auto.
                if (hMode == ScrollbarAuto)
                    setHorizontalScrollbarMode(ScrollbarAlwaysOff); // This causes a horizontal scrollbar to disappear.

                setScrollbarModes(hMode, vMode);
                setScrollbarsSuppressed(false, true);
            } else if (hMode != currentHMode || vMode != currentVMode) {
                setScrollbarModes(hMode, vMode);
            }

            LayoutSize oldSize = m_size;

            m_size = LayoutSize(layoutSize().width(), layoutSize().height());

            if (oldSize != m_size) {
                // It's hard to predict here which of full repaint or per-descendant repaint costs less.
                // For vertical writing mode or width change, it's more likely that per-descendant repaint
                // eventually turns out to be full repaint but with the cost to handle layout states and
                // discrete repaint rects, so marking full repaint here is more likely to cost less.
                // For height only changes, per-descendant repaint is more likely to avoid unnecessary
                // full repaints.
                if (!renderView()->style()->isHorizontalWritingMode() || oldSize.width() != m_size.width())
                    shouldDoFullRepaint = true;

                if (!m_firstLayout) {
                    RenderBox* rootRenderer = document->documentElement() ? document->documentElement()->renderBox() : 0;
                    RenderBox* bodyRenderer = rootRenderer && document->body() ? document->body()->renderBox() : 0;
                    if (bodyRenderer && bodyRenderer->stretchesToViewport())
                        bodyRenderer->setChildNeedsLayout();
                    else if (rootRenderer && rootRenderer->stretchesToViewport())
                        rootRenderer->setChildNeedsLayout();
                }
            }
        }

        layer = rootForThisLayout->enclosingLayer();

        // We need to set m_doFullRepaint before triggering layout as RenderObject::checkForRepaint
        // checks the boolean to disable local repaints.
        m_doFullRepaint |= shouldDoFullRepaint;

        performLayout(rootForThisLayout, inSubtreeLayout);

        m_layoutSubtreeRoot = 0;
    } // Reset m_layoutSchedulingEnabled to its previous value.

    if (!inSubtreeLayout && !toRenderView(rootForThisLayout)->document().printing())
        adjustViewSize();

    layer->updateLayerPositionsAfterLayout(renderView()->layer(), updateLayerPositionFlags(layer, inSubtreeLayout, m_doFullRepaint));

    updateCompositingLayersAfterLayout();

    m_layoutCount++;

    if (AXObjectCache* cache = rootForThisLayout->document().axObjectCache())
        cache->handleLayoutComplete(rootForThisLayout);
    updateAnnotatedRegions();

    ASSERT(!rootForThisLayout->needsLayout());

    if (document->hasListenerType(Document::OVERFLOWCHANGED_LISTENER))
        updateOverflowStatus(layoutSize().width() < contentsWidth(), layoutSize().height() < contentsHeight());

    scheduleOrPerformPostLayoutTasks();

    InspectorInstrumentation::didLayout(cookie, rootForThisLayout);

    m_nestedLayoutCount--;
    if (m_nestedLayoutCount)
        return;

    if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled()) {
        repaintTree(rootForThisLayout);

    } else if (m_doFullRepaint) {
        // FIXME: This isn't really right, since the RenderView doesn't fully encompass
        // the visibleContentRect(). It just happens to work out most of the time,
        // since first layouts and printing don't have you scrolled anywhere.
        renderView()->repaint();
    }

    m_doFullRepaint = false;

#ifndef NDEBUG
    // Post-layout assert that nobody was re-marked as needing layout during layout.
    document->renderer()->assertSubtreeIsLaidOut();
#endif

    // FIXME: It should be not possible to remove the FrameView from the frame/page during layout
    // however m_inPerformLayout is not set for most of this function, so none of our RELEASE_ASSERTS
    // in LocalFrame/Page will fire. One of the post-layout tasks is disconnecting the LocalFrame from
    // the page in fast/frames/crash-remove-iframe-during-object-beforeload-2.html
    // necessitating this check here.
    // ASSERT(frame()->page());
    if (frame().page())
        frame().page()->chrome().client().layoutUpdated(m_frame.get());
}

// The plan is to move to compositor-queried repainting, in which case this
// method would setNeedsRedraw on the GraphicsLayers with invalidations and
// let the compositor pick which to actually draw.
// See http://crbug.com/306706
void FrameView::repaintTree(RenderObject* root)
{
    ASSERT(RuntimeEnabledFeatures::repaintAfterLayoutEnabled());
    ASSERT(!root->needsLayout());
    // We should only repaint for the outer most layout. This works as
    // we continue to track repaint rects until this function is called.
    ASSERT(!m_nestedLayoutCount);

    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("blink.invalidation"), "FrameView::repaintTree");

    // FIXME: really, we're in the repaint phase here, and the compositing queries are legal.
    // Until those states are fully fledged, I'll just disable the ASSERTS.
    DisableCompositingQueryAsserts disabler;

    // If we are set to do a full repaint that means the RenderView will be
    // invalidated. We can then skip issuing of invalidations for the child
    // renderers as they'll be covered by the RenderView.
    if (m_doFullRepaint) {
        RenderView* view = renderView();
        view->repaintAfterLayoutIfNeeded(view->containerForRepaint(), true, view->oldRepaintRect(), &(view->newRepaintRect()));

        // Clear the invalidation flags for the root and child renderers.
        for (RenderObject* renderer = root; renderer; renderer = renderer->nextInPreOrder()) {
            renderer->clearRepaintState();
        }
        return;
    }

    ASSERT(!m_doFullRepaint);

    for (RenderObject* renderer = root; renderer; renderer = renderer->nextInPreOrder()) {
        if ((renderer->onlyNeededPositionedMovementLayout() && renderer->compositingState() != PaintsIntoOwnBacking)
            || (renderer->shouldDoFullRepaintIfSelfPaintingLayer()
                && renderer->hasLayer()
                && toRenderLayerModelObject(renderer)->layer()->isSelfPaintingLayer())) {
            renderer->setShouldDoFullRepaintAfterLayout(true);
        }

        // FIXME: Currently renderers with layers will get repainted when we call updateLayerPositionsAfterLayout.
        // That call should be broken apart to position the layers be done before
        // the repaintTree call so this will repaint everything.
        bool didFullRepaint = false;
        if (!renderer->layoutDidGetCalled()) {
            if (renderer->shouldDoFullRepaintAfterLayout()) {
                renderer->repaint();
                didFullRepaint = true;
            }

        } else {
            didFullRepaint = renderer->repaintAfterLayoutIfNeeded(renderer->containerForRepaint(),
                renderer->shouldDoFullRepaintAfterLayout(), renderer->oldRepaintRect(), &(renderer->newRepaintRect()));
        }

        if (!didFullRepaint)
            renderer->repaintOverflowIfNeeded();

        // Repaint any scrollbars if there is a scrollable area for this renderer.
        if (RenderLayerScrollableArea* area = renderer->enclosingLayer()->scrollableArea()) {
            if (area->hasVerticalBarDamage())
                renderer->repaintRectangle(area->verticalBarDamage());
            if (area->hasHorizontalBarDamage())
                renderer->repaintRectangle(area->horizontalBarDamage());
            area->resetScrollbarDamage();
        }

        // The list box has a verticalScrollbar we may need to repaint.
        if (renderer->isListBox()) {
            RenderListBox* listBox = static_cast<RenderListBox*>(renderer);
            listBox->repaintScrollbarIfNeeded();
        }

        renderer->clearRepaintState();
    }

    // Repaint the frameviews scrollbars if needed
    if (hasVerticalBarDamage())
        invalidateRect(verticalBarDamage());
    if (hasHorizontalBarDamage())
        invalidateRect(horizontalBarDamage());
    resetScrollbarDamage();
}

DocumentLifecycle& FrameView::lifecycle() const
{
    return m_frame->document()->lifecycle();
}

void FrameView::gatherDebugLayoutRects(RenderObject* layoutRoot)
{
    bool isTracing;
    TRACE_EVENT_CATEGORY_GROUP_ENABLED(TRACE_DISABLED_BY_DEFAULT("blink.debug.layout"), &isTracing);
    if (!isTracing)
        return;
    if (!layoutRoot->enclosingLayer()->hasCompositedLayerMapping())
        return;
    GraphicsLayer* graphicsLayer = layoutRoot->enclosingLayer()->compositedLayerMapping()->mainGraphicsLayer();
    if (!graphicsLayer)
        return;

    GraphicsLayerDebugInfo& debugInfo = graphicsLayer->debugInfo();

    debugInfo.currentLayoutRects().clear();
    for (RenderObject* renderer = layoutRoot; renderer; renderer = renderer->nextInPreOrder()) {
        if (renderer->layoutDidGetCalled()) {
            FloatQuad quad = renderer->localToAbsoluteQuad(FloatQuad(renderer->newRepaintRect()));
            LayoutRect rect = quad.enclosingBoundingBox();
            debugInfo.currentLayoutRects().append(rect);
            renderer->setLayoutDidGetCalled(false);
        }
    }
}

RenderBox* FrameView::embeddedContentBox() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return 0;

    RenderObject* firstChild = renderView->firstChild();
    if (!firstChild || !firstChild->isBox())
        return 0;

    // Curently only embedded SVG documents participate in the size-negotiation logic.
    if (firstChild->isSVGRoot())
        return toRenderBox(firstChild);

    return 0;
}


void FrameView::addWidget(RenderWidget* object)
{
    m_widgets.add(object);
}

void FrameView::removeWidget(RenderWidget* object)
{
    m_widgets.remove(object);
}

void FrameView::updateWidgetPositions()
{
    Vector<RefPtr<RenderWidget> > widgets;
    copyToVector(m_widgets, widgets);

    // Script or plugins could detach the frame so abort processing if that happens.

    for (size_t i = 0; i < widgets.size() && renderView(); ++i)
        widgets[i]->updateWidgetPosition();

    for (size_t i = 0; i < widgets.size() && renderView(); ++i)
        widgets[i]->widgetPositionsUpdated();
}

void FrameView::addWidgetToUpdate(RenderEmbeddedObject& object)
{
    ASSERT(isInPerformLayout());
    // Tell the DOM element that it needs a widget update.
    Node* node = object.node();
    ASSERT(node);
    if (isHTMLObjectElement(*node) || isHTMLEmbedElement(*node))
        toHTMLPlugInElement(node)->setNeedsWidgetUpdate(true);

    m_widgetUpdateSet.add(&object);
}

void FrameView::setMediaType(const AtomicString& mediaType)
{
    ASSERT(m_frame->document());
    m_frame->document()->mediaQueryAffectingValueChanged();
    m_mediaType = mediaType;
}

AtomicString FrameView::mediaType() const
{
    // See if we have an override type.
    String overrideType;
    InspectorInstrumentation::applyEmulatedMedia(m_frame.get(), &overrideType);
    if (!overrideType.isNull())
        return AtomicString(overrideType);
    return m_mediaType;
}

void FrameView::adjustMediaTypeForPrinting(bool printing)
{
    if (printing) {
        if (m_mediaTypeWhenNotPrinting.isNull())
            m_mediaTypeWhenNotPrinting = mediaType();
            setMediaType("print");
    } else {
        if (!m_mediaTypeWhenNotPrinting.isNull())
            setMediaType(m_mediaTypeWhenNotPrinting);
        m_mediaTypeWhenNotPrinting = nullAtom;
    }
}

bool FrameView::useSlowRepaints(bool considerOverlap) const
{
    // FIXME: It is incorrect to determine blit-scrolling eligibility using dirty compositing state.
    // https://code.google.com/p/chromium/issues/detail?id=357345
    DisableCompositingQueryAsserts disabler;

    if (m_slowRepaintObjectCount > 0)
        return true;

    if (contentsInCompositedLayer())
        return false;

    // The chromium compositor does not support scrolling a non-composited frame within a composited page through
    // the fast scrolling path, so force slow scrolling in that case.
    if (m_frame->ownerElement() && !hasCompositedContent() && m_frame->page() && m_frame->page()->mainFrame()->view()->hasCompositedContent())
        return true;

    if (m_isOverlapped && considerOverlap)
        return true;

    if (m_cannotBlitToWindow)
        return true;

    if (!m_contentIsOpaque)
        return true;

    if (FrameView* parentView = parentFrameView())
        return parentView->useSlowRepaints(considerOverlap);

    return false;
}

bool FrameView::useSlowRepaintsIfNotOverlapped() const
{
    return useSlowRepaints(false);
}

bool FrameView::shouldAttemptToScrollUsingFastPath() const
{
    return !useSlowRepaints();
}

bool FrameView::contentsInCompositedLayer() const
{
    RenderView* renderView = this->renderView();
    if (renderView && renderView->compositingState() == PaintsIntoOwnBacking) {
        GraphicsLayer* layer = renderView->layer()->compositedLayerMapping()->mainGraphicsLayer();
        if (layer && layer->drawsContent())
            return true;
    }

    return false;
}

void FrameView::setCannotBlitToWindow()
{
    m_cannotBlitToWindow = true;
}

void FrameView::addSlowRepaintObject()
{
    if (!m_slowRepaintObjectCount++) {
        if (Page* page = m_frame->page()) {
            if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
                scrollingCoordinator->frameViewHasSlowRepaintObjectsDidChange(this);
        }
    }
}

void FrameView::removeSlowRepaintObject()
{
    ASSERT(m_slowRepaintObjectCount > 0);
    m_slowRepaintObjectCount--;
    if (!m_slowRepaintObjectCount) {
        if (Page* page = m_frame->page()) {
            if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
                scrollingCoordinator->frameViewHasSlowRepaintObjectsDidChange(this);
        }
    }
}

void FrameView::addViewportConstrainedObject(RenderObject* object)
{
    if (!m_viewportConstrainedObjects)
        m_viewportConstrainedObjects = adoptPtr(new ViewportConstrainedObjectSet);

    if (!m_viewportConstrainedObjects->contains(object)) {
        m_viewportConstrainedObjects->add(object);

        if (Page* page = m_frame->page()) {
            if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
                scrollingCoordinator->frameViewFixedObjectsDidChange(this);
        }
    }
}

void FrameView::removeViewportConstrainedObject(RenderObject* object)
{
    if (m_viewportConstrainedObjects && m_viewportConstrainedObjects->contains(object)) {
        m_viewportConstrainedObjects->remove(object);

        if (Page* page = m_frame->page()) {
            if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
                scrollingCoordinator->frameViewFixedObjectsDidChange(this);
        }
    }
}

LayoutRect FrameView::viewportConstrainedVisibleContentRect() const
{
    LayoutRect viewportRect = visibleContentRect();
    // Ignore overhang. No-op when not using rubber banding.
    viewportRect.setLocation(clampScrollPosition(scrollPosition()));
    return viewportRect;
}

void FrameView::viewportConstrainedVisibleContentSizeChanged(bool widthChanged, bool heightChanged)
{
    // If viewport is not enabled, frameRect change will cause layout size change and then layout.
    // Otherwise, viewport constrained objects need their layout flags set separately to ensure
    // they are positioned correctly.
    if ((m_frame->settings() && !m_frame->settings()->viewportEnabled()) || !hasViewportConstrainedObjects())
        return;

    ViewportConstrainedObjectSet::const_iterator end = m_viewportConstrainedObjects->end();
    for (ViewportConstrainedObjectSet::const_iterator it = m_viewportConstrainedObjects->begin(); it != end; ++it) {
        RenderObject* renderer = *it;
        RenderStyle* style = renderer->style();
        if (widthChanged) {
            if (style->width().isFixed() && (style->left().isAuto() || style->right().isAuto()))
                renderer->setNeedsPositionedMovementLayout();
            else
                renderer->setNeedsLayout();
        }
        if (heightChanged) {
            if (style->height().isFixed() && (style->top().isAuto() || style->bottom().isAuto()))
                renderer->setNeedsPositionedMovementLayout();
            else
                renderer->setNeedsLayout();
        }
    }
}

bool FrameView::shouldPlaceVerticalScrollbarOnLeft() const
{
    // FIXME: Mainframe scrollbar placement should respect the embedding application RTL UI policy.
    // See crbug.com/249860.
    if (isMainFrame())
        return false;

    Document* document = m_frame->document();
    if (!document)
        return false;

    // <body> inherits 'direction' from <html>, so it can safaly be used
    // to dictate the frame vertical scrollbar placement.
    if (!document->body() || !document->body()->renderer())
        return false;

    return document->body()->renderer()->style()->shouldPlaceBlockDirectionScrollbarOnLogicalLeft();
}

IntSize FrameView::scrollOffsetForFixedPosition() const
{
    return toIntSize(clampScrollPosition(scrollPosition()));
}

IntPoint FrameView::lastKnownMousePosition() const
{
    return m_frame->eventHandler().lastKnownMousePosition();
}

bool FrameView::shouldSetCursor() const
{
    Page* page = frame().page();
    return page && page->visibilityState() != PageVisibilityStateHidden && page->focusController().isActive();
}

void FrameView::scrollContentsIfNeededRecursive()
{
    scrollContentsIfNeeded();

    for (LocalFrame* child = m_frame->tree().firstChild(); child; child = child->tree().nextSibling()) {
        if (FrameView* view = child->view())
            view->scrollContentsIfNeededRecursive();
    }
}

void FrameView::scrollContentsIfNeeded()
{
    bool didScroll = !pendingScrollDelta().isZero();
    ScrollView::scrollContentsIfNeeded();
    if (didScroll)
        updateFixedElementRepaintRectsAfterScroll();
}

bool FrameView::scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect)
{
    if (!m_viewportConstrainedObjects || m_viewportConstrainedObjects->isEmpty()) {
        hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
        return true;
    }

    const bool isCompositedContentLayer = contentsInCompositedLayer();

    // Get the rects of the fixed objects visible in the rectToScroll
    Region regionToUpdate;
    ViewportConstrainedObjectSet::const_iterator end = m_viewportConstrainedObjects->end();
    for (ViewportConstrainedObjectSet::const_iterator it = m_viewportConstrainedObjects->begin(); it != end; ++it) {
        RenderObject* renderer = *it;
        // m_viewportConstrainedObjects should not contain non-viewport constrained objects.
        ASSERT(renderer->style()->hasViewportConstrainedPosition());

        // Fixed items should always have layers.
        ASSERT(renderer->hasLayer());
        RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();

        // Layers that paint into their ancestor or into a grouped backing will still need
        // to apply a repaint invalidation. If the layer paints into its own backing, then
        // it does not need repainting just to scroll.
        if (layer->compositingState() == PaintsIntoOwnBacking)
            continue;

        if (layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForBoundsOutOfView
            || layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForNoVisibleContent) {
            // Don't invalidate for invisible fixed layers.
            continue;
        }

        if (layer->hasAncestorWithFilterOutsets()) {
            // If the fixed layer has a blur/drop-shadow filter applied on at least one of its parents, we cannot
            // scroll using the fast path, otherwise the outsets of the filter will be moved around the page.
            return false;
        }

        IntRect updateRect = pixelSnappedIntRect(layer->repainter().repaintRectIncludingNonCompositingDescendants());

        RenderLayer* enclosingCompositingLayer = layer->enclosingCompositingLayer(ExcludeSelf);
        if (enclosingCompositingLayer && !enclosingCompositingLayer->renderer()->isRenderView()) {
            // If the fixed-position layer is contained by a composited layer that is not its containing block,
            // then we have to invlidate that enclosing layer, not the RenderView.
            updateRect.moveBy(scrollPosition());
            IntRect previousRect = updateRect;
            previousRect.move(scrollDelta);
            updateRect.unite(previousRect);
            enclosingCompositingLayer->repainter().setBackingNeedsRepaintInRect(updateRect);
        } else {
            // Coalesce the repaints that will be issued to the renderView.
            updateRect = contentsToRootView(updateRect);
            if (!isCompositedContentLayer && clipsRepaints())
                updateRect.intersect(rectToScroll);
            if (!updateRect.isEmpty())
                regionToUpdate.unite(updateRect);
        }
    }

    // 1) scroll
    hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);

    // 2) update the area of fixed objects that has been invalidated
    Vector<IntRect> subRectsToUpdate = regionToUpdate.rects();
    size_t viewportConstrainedObjectsCount = subRectsToUpdate.size();
    for (size_t i = 0; i < viewportConstrainedObjectsCount; ++i) {
        IntRect updateRect = subRectsToUpdate[i];
        IntRect scrolledRect = updateRect;
        scrolledRect.move(-scrollDelta);
        updateRect.unite(scrolledRect);
        if (isCompositedContentLayer) {
            updateRect = rootViewToContents(updateRect);
            ASSERT(renderView());
            renderView()->layer()->repainter().setBackingNeedsRepaintInRect(updateRect);
            continue;
        }
        if (clipsRepaints())
            updateRect.intersect(rectToScroll);
        hostWindow()->invalidateContentsAndRootView(updateRect);
    }

    return true;
}

void FrameView::scrollContentsSlowPath(const IntRect& updateRect)
{
    if (contentsInCompositedLayer()) {
        IntRect updateRect = visibleContentRect();
        ASSERT(renderView());
        renderView()->layer()->repainter().setBackingNeedsRepaintInRect(updateRect);
    }
    if (RenderPart* frameRenderer = m_frame->ownerRenderer()) {
        if (isEnclosedInCompositingLayer()) {
            LayoutRect rect(frameRenderer->borderLeft() + frameRenderer->paddingLeft(),
                            frameRenderer->borderTop() + frameRenderer->paddingTop(),
                            visibleWidth(), visibleHeight());
            frameRenderer->repaintRectangle(rect);
            return;
        }
    }

    ScrollView::scrollContentsSlowPath(updateRect);
}

// Note that this gets called at painting time.
void FrameView::setIsOverlapped(bool isOverlapped)
{
    m_isOverlapped = isOverlapped;
}

void FrameView::setContentIsOpaque(bool contentIsOpaque)
{
    m_contentIsOpaque = contentIsOpaque;
}

void FrameView::restoreScrollbar()
{
    setScrollbarsSuppressed(false);
}

bool FrameView::scrollToFragment(const KURL& url)
{
    // If our URL has no ref, then we have no place we need to jump to.
    // OTOH If CSS target was set previously, we want to set it to 0, recalc
    // and possibly repaint because :target pseudo class may have been
    // set (see bug 11321).
    if (!url.hasFragmentIdentifier() && !m_frame->document()->cssTarget())
        return false;

    String fragmentIdentifier = url.fragmentIdentifier();
    if (scrollToAnchor(fragmentIdentifier))
        return true;

    // Try again after decoding the ref, based on the document's encoding.
    if (m_frame->document()->encoding().isValid())
        return scrollToAnchor(decodeURLEscapeSequences(fragmentIdentifier, m_frame->document()->encoding()));

    return false;
}

bool FrameView::scrollToAnchor(const String& name)
{
    ASSERT(m_frame->document());

    if (!m_frame->document()->haveStylesheetsLoaded()) {
        m_frame->document()->setGotoAnchorNeededAfterStylesheetsLoad(true);
        return false;
    }

    m_frame->document()->setGotoAnchorNeededAfterStylesheetsLoad(false);

    Element* anchorNode = m_frame->document()->findAnchor(name);

    // Setting to null will clear the current target.
    m_frame->document()->setCSSTarget(anchorNode);

    if (m_frame->document()->isSVGDocument()) {
        if (SVGSVGElement* svg = toSVGDocument(m_frame->document())->rootElement()) {
            svg->setupInitialView(name, anchorNode);
            if (!anchorNode)
                return true;
        }
    }

    // Implement the rule that "" and "top" both mean top of page as in other browsers.
    if (!anchorNode && !(name.isEmpty() || equalIgnoringCase(name, "top")))
        return false;

    maintainScrollPositionAtAnchor(anchorNode ? static_cast<Node*>(anchorNode) : m_frame->document());

    // If the anchor accepts keyboard focus, move focus there to aid users relying on keyboard navigation.
    if (anchorNode && anchorNode->isFocusable())
        m_frame->document()->setFocusedElement(anchorNode);

    return true;
}

void FrameView::maintainScrollPositionAtAnchor(Node* anchorNode)
{
    m_maintainScrollPositionAnchor = anchorNode;
    if (!m_maintainScrollPositionAnchor)
        return;

    // We need to update the layout before scrolling, otherwise we could
    // really mess things up if an anchor scroll comes at a bad moment.
    m_frame->document()->updateRenderTreeIfNeeded();
    // Only do a layout if changes have occurred that make it necessary.
    RenderView* renderView = this->renderView();
    if (renderView && renderView->needsLayout())
        layout();
    else
        scrollToAnchor();
}

void FrameView::scrollElementToRect(Element* element, const IntRect& rect)
{
    m_frame->document()->updateLayoutIgnorePendingStylesheets();

    LayoutRect bounds = element->boundingBox();
    int centeringOffsetX = (rect.width() - bounds.width()) / 2;
    int centeringOffsetY = (rect.height() - bounds.height()) / 2;
    setScrollPosition(IntPoint(bounds.x() - centeringOffsetX - rect.x(), bounds.y() - centeringOffsetY - rect.y()));
}

void FrameView::setScrollPosition(const IntPoint& scrollPoint)
{
    TemporaryChange<bool> changeInProgrammaticScroll(m_inProgrammaticScroll, true);
    m_maintainScrollPositionAnchor = nullptr;

    IntPoint newScrollPosition = adjustScrollPositionWithinRange(scrollPoint);

    if (newScrollPosition == scrollPosition())
        return;

    ScrollView::setScrollPosition(newScrollPosition);
}

void FrameView::setScrollPositionNonProgrammatically(const IntPoint& scrollPoint)
{
    IntPoint newScrollPosition = adjustScrollPositionWithinRange(scrollPoint);

    if (newScrollPosition == scrollPosition())
        return;

    TemporaryChange<bool> changeInProgrammaticScroll(m_inProgrammaticScroll, false);
    notifyScrollPositionChanged(newScrollPosition);
}

IntSize FrameView::layoutSize(IncludeScrollbarsInRect scrollbarInclusion) const
{
    return scrollbarInclusion == ExcludeScrollbars ? excludeScrollbars(m_layoutSize) : m_layoutSize;
}

void FrameView::setLayoutSize(const IntSize& size)
{
    ASSERT(!layoutSizeFixedToFrameSize());

    setLayoutSizeInternal(size);
}

void FrameView::scrollPositionChanged()
{
    setWasScrolledByUser(true);

    Document* document = m_frame->document();
    document->enqueueScrollEventForNode(document);

    m_frame->eventHandler().dispatchFakeMouseMoveEventSoon();

    if (RenderView* renderView = document->renderView()) {
        if (renderView->usesCompositing())
            renderView->compositor()->frameViewDidScroll();
    }

    if (m_didScrollTimer.isActive())
        m_didScrollTimer.stop();
    m_didScrollTimer.startOneShot(resourcePriorityUpdateDelayAfterScroll, FROM_HERE);

    if (AXObjectCache* cache = m_frame->document()->existingAXObjectCache())
        cache->handleScrollPositionChanged(this);

    frame().loader().saveScrollState();
}

void FrameView::didScrollTimerFired(Timer<FrameView>*)
{
    if (m_frame->document() && m_frame->document()->renderer()) {
        ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->updateAllImageResourcePriorities();
    }
}

void FrameView::updateLayersAndCompositingAfterScrollIfNeeded()
{
    // Nothing to do after scrolling if there are no fixed position elements.
    if (!hasViewportConstrainedObjects())
        return;

    RefPtr<FrameView> protect(this);

    // If there fixed position elements, scrolling may cause compositing layers to change.
    // Update widget and layer positions after scrolling, but only if we're not inside of
    // layout.
    if (!m_nestedLayoutCount) {
        updateWidgetPositions();
        if (RenderView* renderView = this->renderView())
            renderView->layer()->updateLayerPositionsAfterDocumentScroll();
    }

    // Compositing layers may change after scrolling.
    // FIXME: Maybe no longer needed after we land squashing and kill overlap testing?
    if (RenderView* renderView = this->renderView())
        renderView->compositor()->setNeedsCompositingUpdate(CompositingUpdateOnScroll);
}

void FrameView::updateFixedElementRepaintRectsAfterScroll()
{
    if (!hasViewportConstrainedObjects())
        return;

    // Update the repaint rects for fixed elements after scrolling and invalidation to reflect
    // the new scroll position.
    ViewportConstrainedObjectSet::const_iterator end = m_viewportConstrainedObjects->end();
    for (ViewportConstrainedObjectSet::const_iterator it = m_viewportConstrainedObjects->begin(); it != end; ++it) {
        RenderObject* renderer = *it;
        // m_viewportConstrainedObjects should not contain non-viewport constrained objects.
        ASSERT(renderer->style()->hasViewportConstrainedPosition());

        // Fixed items should always have layers.
        ASSERT(renderer->hasLayer());

        RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();

        // Don't need to do this for composited fixed items.
        if (layer->compositingState() == PaintsIntoOwnBacking)
            continue;

        // Also don't need to do this for invisible items.
        if (layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForBoundsOutOfView
            || layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForNoVisibleContent)
            continue;

        layer->repainter().computeRepaintRectsIncludingDescendants();
    }
}

bool FrameView::shouldRubberBandInDirection(ScrollDirection direction) const
{
    Page* page = frame().page();
    if (!page)
        return ScrollView::shouldRubberBandInDirection(direction);
    return page->chrome().client().shouldRubberBandInDirection(direction);
}

bool FrameView::isRubberBandInProgress() const
{
    if (scrollbarsSuppressed())
        return false;

    // If the main thread updates the scroll position for this FrameView, we should return
    // ScrollAnimator::isRubberBandInProgress().
    if (ScrollAnimator* scrollAnimator = existingScrollAnimator())
        return scrollAnimator->isRubberBandInProgress();

    return false;
}

HostWindow* FrameView::hostWindow() const
{
    Page* page = frame().page();
    if (!page)
        return 0;
    return &page->chrome();
}

void FrameView::repaintContentRectangle(const IntRect& r)
{
    ASSERT(repaintAllowed());
    ASSERT(!m_frame->ownerElement());

    if (m_isTrackingRepaints) {
        IntRect repaintRect = r;
        repaintRect.move(-scrollOffset());
        m_trackedRepaintRects.append(repaintRect);
    }

    ScrollView::repaintContentRectangle(r);
}

void FrameView::contentsResized()
{
    if (isMainFrame() && m_frame->document()) {
        if (FastTextAutosizer* textAutosizer = m_frame->document()->fastTextAutosizer())
            textAutosizer->updatePageInfoInAllFrames();
    }

    ScrollView::contentsResized();
    if (RenderView* renderView = this->renderView()) {
        // Don't directly repaint layer in setNeedsLayout. We'll handle repaint in layout().
        renderView->setNeedsLayout(MarkContainingBlockChain, 0, DontRepaintLayer);
    }
}

void FrameView::scrollbarExistenceDidChange()
{
    // We check to make sure the view is attached to a frame() as this method can
    // be triggered before the view is attached by LocalFrame::createView(...) setting
    // various values such as setScrollBarModes(...) for example.  An ASSERT is
    // triggered when a view is layout before being attached to a frame().
    if (!frame().view())
        return;

    // Note that simply having overlay scrollbars is not sufficient to be
    // certain that scrollbars' presence does not impact layout. This should
    // also check if custom scrollbars (as reported by shouldUseCustomScrollbars)
    // are in use as well.
    // http://crbug.com/269692
    bool useOverlayScrollbars = ScrollbarTheme::theme()->usesOverlayScrollbars();

    if (!useOverlayScrollbars && needsLayout())
        layout();

    if (renderView() && renderView()->usesCompositing()) {
        renderView()->compositor()->frameViewScrollbarsExistenceDidChange();

        if (!useOverlayScrollbars)
            renderView()->compositor()->frameViewDidChangeSize();
    }
}

void FrameView::handleLoadCompleted()
{
    // Once loading has completed, allow autoSize one last opportunity to
    // reduce the size of the frame.
    autoSizeIfEnabled();
}

void FrameView::scheduleRelayout()
{
    ASSERT(m_frame->view() == this);

    if (isSubtreeLayout()) {
        m_layoutSubtreeRoot->markContainingBlocksForLayout(false);
        m_layoutSubtreeRoot = 0;
    }
    if (!m_layoutSchedulingEnabled)
        return;
    if (!needsLayout())
        return;
    if (!m_frame->document()->shouldScheduleLayout())
        return;
    InspectorInstrumentation::didInvalidateLayout(m_frame.get());

    if (m_hasPendingLayout)
        return;
    m_hasPendingLayout = true;
    page()->animator().scheduleVisualUpdate();
}

static bool isObjectAncestorContainerOf(RenderObject* ancestor, RenderObject* descendant)
{
    for (RenderObject* r = descendant; r; r = r->container()) {
        if (r == ancestor)
            return true;
    }
    return false;
}

void FrameView::scheduleRelayoutOfSubtree(RenderObject* relayoutRoot)
{
    ASSERT(m_frame->view() == this);

    RenderView* renderView = this->renderView();
    if (renderView && renderView->needsLayout()) {
        if (relayoutRoot)
            relayoutRoot->markContainingBlocksForLayout(false);
        return;
    }

    if (layoutPending() || !m_layoutSchedulingEnabled) {
        if (m_layoutSubtreeRoot != relayoutRoot) {
            if (isObjectAncestorContainerOf(m_layoutSubtreeRoot, relayoutRoot)) {
                // Keep the current root
                relayoutRoot->markContainingBlocksForLayout(false, m_layoutSubtreeRoot);
                ASSERT(!m_layoutSubtreeRoot->container() || !m_layoutSubtreeRoot->container()->needsLayout());
            } else if (isSubtreeLayout() && isObjectAncestorContainerOf(relayoutRoot, m_layoutSubtreeRoot)) {
                // Re-root at relayoutRoot
                m_layoutSubtreeRoot->markContainingBlocksForLayout(false, relayoutRoot);
                m_layoutSubtreeRoot = relayoutRoot;
                ASSERT(!m_layoutSubtreeRoot->container() || !m_layoutSubtreeRoot->container()->needsLayout());
                InspectorInstrumentation::didInvalidateLayout(m_frame.get());
            } else {
                // Just do a full relayout
                if (isSubtreeLayout())
                    m_layoutSubtreeRoot->markContainingBlocksForLayout(false);
                m_layoutSubtreeRoot = 0;
                relayoutRoot->markContainingBlocksForLayout(false);
                InspectorInstrumentation::didInvalidateLayout(m_frame.get());
            }
        }
    } else if (m_layoutSchedulingEnabled) {
        m_layoutSubtreeRoot = relayoutRoot;
        ASSERT(!m_layoutSubtreeRoot->container() || !m_layoutSubtreeRoot->container()->needsLayout());
        InspectorInstrumentation::didInvalidateLayout(m_frame.get());
        m_hasPendingLayout = true;
        page()->animator().scheduleVisualUpdate();
    }
}

bool FrameView::layoutPending() const
{
    return m_hasPendingLayout;
}

bool FrameView::isInPerformLayout() const
{
    ASSERT(m_inPerformLayout == (lifecycle().state() == DocumentLifecycle::InPerformLayout));
    return m_inPerformLayout;
}

bool FrameView::needsLayout() const
{
    // This can return true in cases where the document does not have a body yet.
    // Document::shouldScheduleLayout takes care of preventing us from scheduling
    // layout in that case.

    RenderView* renderView = this->renderView();
    return layoutPending()
        || (renderView && renderView->needsLayout())
        || isSubtreeLayout();
}

void FrameView::setNeedsLayout()
{
    if (RenderView* renderView = this->renderView())
        renderView->setNeedsLayout();
}

bool FrameView::isTransparent() const
{
    return m_isTransparent;
}

void FrameView::setTransparent(bool isTransparent)
{
    m_isTransparent = isTransparent;
    DisableCompositingQueryAsserts disabler;
    if (renderView() && renderView()->layer()->hasCompositedLayerMapping())
        renderView()->layer()->compositedLayerMapping()->updateContentsOpaque();
}

bool FrameView::hasOpaqueBackground() const
{
    return !m_isTransparent && !m_baseBackgroundColor.hasAlpha();
}

Color FrameView::baseBackgroundColor() const
{
    return m_baseBackgroundColor;
}

void FrameView::setBaseBackgroundColor(const Color& backgroundColor)
{
    m_baseBackgroundColor = backgroundColor;

    if (renderView() && renderView()->layer()->hasCompositedLayerMapping()) {
        CompositedLayerMappingPtr compositedLayerMapping = renderView()->layer()->compositedLayerMapping();
        compositedLayerMapping->updateContentsOpaque();
        if (compositedLayerMapping->mainGraphicsLayer())
            compositedLayerMapping->mainGraphicsLayer()->setNeedsDisplay();
    }
    recalculateScrollbarOverlayStyle();
}

void FrameView::updateBackgroundRecursively(const Color& backgroundColor, bool transparent)
{
    for (LocalFrame* frame = m_frame.get(); frame; frame = frame->tree().traverseNext(m_frame.get())) {
        if (FrameView* view = frame->view()) {
            view->setTransparent(transparent);
            view->setBaseBackgroundColor(backgroundColor);
        }
    }
}

void FrameView::scrollToAnchor()
{
    RefPtr<Node> anchorNode = m_maintainScrollPositionAnchor;
    if (!anchorNode)
        return;

    if (!anchorNode->renderer())
        return;

    LayoutRect rect;
    if (anchorNode != m_frame->document())
        rect = anchorNode->boundingBox();

    // Scroll nested layers and frames to reveal the anchor.
    // Align to the top and to the closest side (this matches other browsers).
    anchorNode->renderer()->scrollRectToVisible(rect, ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignTopAlways);

    if (AXObjectCache* cache = m_frame->document()->existingAXObjectCache())
        cache->handleScrolledToAnchor(anchorNode.get());

    // scrollRectToVisible can call into setScrollPosition(), which resets m_maintainScrollPositionAnchor.
    m_maintainScrollPositionAnchor = anchorNode;
}

bool FrameView::updateWidgets()
{
    // This is always called from updateWidgetsTimerFired.
    // m_updateWidgetsTimer should only be scheduled if we have widgets to update.
    // Thus I believe we can stop checking isEmpty here, and just ASSERT isEmpty:
    ASSERT(!m_widgetUpdateSet.isEmpty());
    if (m_nestedLayoutCount > 1 || m_widgetUpdateSet.isEmpty())
        return true;

    // Need to swap because script will run inside the below loop and invalidate the iterator.
    EmbeddedObjectSet objects;
    objects.swap(m_widgetUpdateSet);

    for (EmbeddedObjectSet::iterator it = objects.begin(); it != objects.end(); ++it) {
        RenderEmbeddedObject& object = **it;
        HTMLPlugInElement* element = toHTMLPlugInElement(object.node());

        // The object may have already been destroyed (thus node cleared),
        // but FrameView holds a manual ref, so it won't have been deleted.
        if (!element)
            continue;

        // No need to update if it's already crashed or known to be missing.
        if (object.showsUnavailablePluginIndicator())
            continue;

        if (element->needsWidgetUpdate())
            element->updateWidget();
        object.updateWidgetPosition();

        // Prevent plugins from causing infinite updates of themselves.
        // FIXME: Do we really need to prevent this?
        m_widgetUpdateSet.remove(&object);
    }

    return m_widgetUpdateSet.isEmpty();
}

void FrameView::updateWidgetsTimerFired(Timer<FrameView>*)
{
    ASSERT(!isInPerformLayout());
    RefPtr<FrameView> protect(this);
    m_updateWidgetsTimer.stop();
    for (unsigned i = 0; i < maxUpdateWidgetsIterations; ++i) {
        if (updateWidgets())
            return;
    }
}

void FrameView::flushAnyPendingPostLayoutTasks()
{
    ASSERT(!isInPerformLayout());
    if (m_postLayoutTasksTimer.isActive())
        performPostLayoutTasks();
    if (m_updateWidgetsTimer.isActive())
        updateWidgetsTimerFired(0);
}

void FrameView::scheduleUpdateWidgetsIfNecessary()
{
    ASSERT(!isInPerformLayout());
    if (m_updateWidgetsTimer.isActive() || m_widgetUpdateSet.isEmpty())
        return;
    m_updateWidgetsTimer.startOneShot(0, FROM_HERE);
}

void FrameView::performPostLayoutTasks()
{
    // FIXME: We can reach here, even when the page is not active!
    // http/tests/inspector/elements/html-link-import.html and many other
    // tests hit that case.
    // We should ASSERT(isActive()); or at least return early if we can!
    ASSERT(!isInPerformLayout()); // Always before or after performLayout(), part of the highest-level layout() call.
    TRACE_EVENT0("webkit", "FrameView::performPostLayoutTasks");
    RefPtr<FrameView> protect(this);

    m_postLayoutTasksTimer.stop();

    m_frame->selection().setCaretRectNeedsUpdate();

    {
        // Hits in compositing/overflow/do-not-repaint-if-scrolling-composited-layers.html
        DisableCompositingQueryAsserts disabler;
        m_frame->selection().updateAppearance();
    }

    ASSERT(m_frame->document());
    if (m_nestedLayoutCount <= 1) {
        if (m_firstLayoutCallbackPending)
            m_firstLayoutCallbackPending = false;

        // Ensure that we always send this eventually.
        if (!m_frame->document()->parsing() && m_frame->loader().stateMachine()->committedFirstRealDocumentLoad())
            m_isVisuallyNonEmpty = true;

        // If the layout was done with pending sheets, we are not in fact visually non-empty yet.
        if (m_isVisuallyNonEmpty && !m_frame->document()->didLayoutWithPendingStylesheets() && m_firstVisuallyNonEmptyLayoutCallbackPending) {
            m_firstVisuallyNonEmptyLayoutCallbackPending = false;
            // FIXME: This callback is probably not needed, but is currently used
            // by android for setting the background color.
            m_frame->loader().client()->dispatchDidFirstVisuallyNonEmptyLayout();
        }
    }

    FontFaceSet::didLayout(*m_frame->document());

    updateWidgetPositions();

    // Plugins could have torn down the page inside updateWidgetPositions().
    if (!renderView())
        return;

    scheduleUpdateWidgetsIfNecessary();

    if (Page* page = m_frame->page()) {
        if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
            scrollingCoordinator->notifyLayoutUpdated();
    }

    scrollToAnchor();

    sendResizeEventIfNeeded();
}

void FrameView::sendResizeEventIfNeeded()
{
    ASSERT(m_frame);

    RenderView* renderView = this->renderView();
    if (!renderView || renderView->document().printing())
        return;

    IntSize currentSize = layoutSize(IncludeScrollbars);
    float currentZoomFactor = renderView->style()->zoom();

    bool shouldSendResizeEvent = currentSize != m_lastViewportSize || currentZoomFactor != m_lastZoomFactor;

    m_lastViewportSize = currentSize;
    m_lastZoomFactor = currentZoomFactor;

    if (!shouldSendResizeEvent)
        return;

    m_frame->document()->enqueueResizeEvent();

    if (isMainFrame())
        InspectorInstrumentation::didResizeMainFrame(m_frame->page());
}

void FrameView::postLayoutTimerFired(Timer<FrameView>*)
{
    performPostLayoutTasks();
}

void FrameView::updateCounters()
{
    RenderView* view = renderView();
    if (!view->hasRenderCounters())
        return;

    for (RenderObject* renderer = view; renderer; renderer = renderer->nextInPreOrder()) {
        if (!renderer->isCounter())
            continue;

        toRenderCounter(renderer)->updateCounter();
    }
}

void FrameView::autoSizeIfEnabled()
{
    if (!m_shouldAutoSize)
        return;

    if (m_inAutoSize)
        return;

    TemporaryChange<bool> changeInAutoSize(m_inAutoSize, true);

    Document* document = frame().document();
    if (!document || !document->isActive())
        return;

    Element* documentElement = document->documentElement();
    if (!documentElement)
        return;

    // If this is the first time we run autosize, start from small height and
    // allow it to grow.
    if (!m_didRunAutosize)
        resize(frameRect().width(), m_minAutoSize.height());

    IntSize size = frameRect().size();

    // Do the resizing twice. The first time is basically a rough calculation using the preferred width
    // which may result in a height change during the second iteration.
    for (int i = 0; i < 2; i++) {
        // Update various sizes including contentsSize, scrollHeight, etc.
        document->updateLayoutIgnorePendingStylesheets();

        RenderView* renderView = document->renderView();
        if (!renderView)
            return;

        int width = renderView->minPreferredLogicalWidth();

        RenderBox* documentRenderBox = documentElement->renderBox();
        if (!documentRenderBox)
            return;

        int height = documentRenderBox->scrollHeight();
        IntSize newSize(width, height);

        // Check to see if a scrollbar is needed for a given dimension and
        // if so, increase the other dimension to account for the scrollbar.
        // Since the dimensions are only for the view rectangle, once a
        // dimension exceeds the maximum, there is no need to increase it further.
        if (newSize.width() > m_maxAutoSize.width()) {
            RefPtr<Scrollbar> localHorizontalScrollbar = horizontalScrollbar();
            if (!localHorizontalScrollbar)
                localHorizontalScrollbar = createScrollbar(HorizontalScrollbar);
            if (!localHorizontalScrollbar->isOverlayScrollbar())
                newSize.setHeight(newSize.height() + localHorizontalScrollbar->height());

            // Don't bother checking for a vertical scrollbar because the width is at
            // already greater the maximum.
        } else if (newSize.height() > m_maxAutoSize.height()) {
            RefPtr<Scrollbar> localVerticalScrollbar = verticalScrollbar();
            if (!localVerticalScrollbar)
                localVerticalScrollbar = createScrollbar(VerticalScrollbar);
            if (!localVerticalScrollbar->isOverlayScrollbar())
                newSize.setWidth(newSize.width() + localVerticalScrollbar->width());

            // Don't bother checking for a horizontal scrollbar because the height is
            // already greater the maximum.
        }

        // Ensure the size is at least the min bounds.
        newSize = newSize.expandedTo(m_minAutoSize);

        // Bound the dimensions by the max bounds and determine what scrollbars to show.
        ScrollbarMode horizonalScrollbarMode = ScrollbarAlwaysOff;
        if (newSize.width() > m_maxAutoSize.width()) {
            newSize.setWidth(m_maxAutoSize.width());
            horizonalScrollbarMode = ScrollbarAlwaysOn;
        }
        ScrollbarMode verticalScrollbarMode = ScrollbarAlwaysOff;
        if (newSize.height() > m_maxAutoSize.height()) {
            newSize.setHeight(m_maxAutoSize.height());
            verticalScrollbarMode = ScrollbarAlwaysOn;
        }

        if (newSize == size)
            continue;

        // While loading only allow the size to increase (to avoid twitching during intermediate smaller states)
        // unless autoresize has just been turned on or the maximum size is smaller than the current size.
        if (m_didRunAutosize && size.height() <= m_maxAutoSize.height() && size.width() <= m_maxAutoSize.width()
            && !m_frame->document()->loadEventFinished() && (newSize.height() < size.height() || newSize.width() < size.width()))
            break;

        resize(newSize.width(), newSize.height());
        // Force the scrollbar state to avoid the scrollbar code adding them and causing them to be needed. For example,
        // a vertical scrollbar may cause text to wrap and thus increase the height (which is the only reason the scollbar is needed).
        setVerticalScrollbarLock(false);
        setHorizontalScrollbarLock(false);
        setScrollbarModes(horizonalScrollbarMode, verticalScrollbarMode, true, true);
    }
    m_didRunAutosize = true;
}

void FrameView::updateOverflowStatus(bool horizontalOverflow, bool verticalOverflow)
{
    if (!m_viewportRenderer)
        return;

    if (m_overflowStatusDirty) {
        m_horizontalOverflow = horizontalOverflow;
        m_verticalOverflow = verticalOverflow;
        m_overflowStatusDirty = false;
        return;
    }

    bool horizontalOverflowChanged = (m_horizontalOverflow != horizontalOverflow);
    bool verticalOverflowChanged = (m_verticalOverflow != verticalOverflow);

    if (horizontalOverflowChanged || verticalOverflowChanged) {
        m_horizontalOverflow = horizontalOverflow;
        m_verticalOverflow = verticalOverflow;

        RefPtrWillBeRawPtr<OverflowEvent> event = OverflowEvent::create(horizontalOverflowChanged, horizontalOverflow, verticalOverflowChanged, verticalOverflow);
        event->setTarget(m_viewportRenderer->node());
        m_frame->document()->enqueueAnimationFrameEvent(event.release());
    }

}

IntRect FrameView::windowClipRect(IncludeScrollbarsInRect scrollbarInclusion) const
{
    ASSERT(m_frame->view() == this);

    if (paintsEntireContents())
        return IntRect(IntPoint(), contentsSize());

    // Set our clip rect to be our contents.
    IntRect clipRect = contentsToWindow(visibleContentRect(scrollbarInclusion));
    if (!m_frame->ownerElement())
        return clipRect;

    // Take our owner element and get its clip rect.
    HTMLFrameOwnerElement* ownerElement = m_frame->ownerElement();
    FrameView* parentView = ownerElement->document().view();
    if (parentView)
        clipRect.intersect(parentView->windowClipRectForFrameOwner(ownerElement));
    return clipRect;
}

IntRect FrameView::windowClipRectForFrameOwner(const HTMLFrameOwnerElement* ownerElement) const
{
    // The renderer can sometimes be null when style="display:none" interacts
    // with external content and plugins.
    if (!ownerElement->renderer())
        return windowClipRect();

    // If we have no layer, just return our window clip rect.
    const RenderLayer* enclosingLayer = ownerElement->renderer()->enclosingLayer();
    if (!enclosingLayer)
        return windowClipRect();

    // FIXME: childrenClipRect relies on compositingState, which is not necessarily up to date.
    // https://code.google.com/p/chromium/issues/detail?id=343769
    DisableCompositingQueryAsserts disabler;

    // Apply the clip from the layer.
    IntRect clipRect = contentsToWindow(pixelSnappedIntRect(enclosingLayer->clipper().childrenClipRect()));
    return intersection(clipRect, windowClipRect());
}

bool FrameView::isActive() const
{
    Page* page = frame().page();
    return page && page->focusController().isActive();
}

void FrameView::scrollTo(const IntSize& newOffset)
{
    LayoutSize offset = scrollOffset();
    ScrollView::scrollTo(newOffset);
    if (offset != scrollOffset()) {
        updateLayersAndCompositingAfterScrollIfNeeded();
        scrollPositionChanged();
    }
    frame().loader().client()->didChangeScrollOffset();
}

void FrameView::invalidateScrollbarRect(Scrollbar* scrollbar, const IntRect& rect)
{
    // Add in our offset within the FrameView.
    IntRect dirtyRect = rect;
    dirtyRect.moveBy(scrollbar->location());

    if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled() && isInPerformLayout()) {
        if (scrollbar == verticalScrollbar()) {
            m_verticalBarDamage = dirtyRect;
            m_hasVerticalBarDamage = true;
        } else {
            m_horizontalBarDamage = dirtyRect;
            m_hasHorizontalBarDamage = true;
        }
    } else {
        invalidateRect(dirtyRect);
    }
}

void FrameView::getTickmarks(Vector<IntRect>& tickmarks) const
{
    if (!m_tickmarks.isEmpty())
        tickmarks = m_tickmarks;
    else
        tickmarks = frame().document()->markers().renderedRectsForMarkers(DocumentMarker::TextMatch);
}

IntRect FrameView::windowResizerRect() const
{
    Page* page = frame().page();
    if (!page)
        return IntRect();
    return page->chrome().windowResizerRect();
}

void FrameView::setVisibleContentScaleFactor(float visibleContentScaleFactor)
{
    if (m_visibleContentScaleFactor == visibleContentScaleFactor)
        return;

    m_visibleContentScaleFactor = visibleContentScaleFactor;
    updateScrollbars(scrollOffset());
}

void FrameView::setInputEventsTransformForEmulation(const IntSize& offset, float contentScaleFactor)
{
    m_inputEventsOffsetForEmulation = offset;
    m_inputEventsScaleFactorForEmulation = contentScaleFactor;
}

IntSize FrameView::inputEventsOffsetForEmulation() const
{
    return m_inputEventsOffsetForEmulation;
}

float FrameView::inputEventsScaleFactor() const
{
    return visibleContentScaleFactor() * m_inputEventsScaleFactorForEmulation;
}

bool FrameView::scrollbarsCanBeActive() const
{
    if (m_frame->view() != this)
        return false;

    return !!m_frame->document();
}

IntRect FrameView::scrollableAreaBoundingBox() const
{
    RenderPart* ownerRenderer = frame().ownerRenderer();
    if (!ownerRenderer)
        return frameRect();

    return ownerRenderer->absoluteContentQuad().enclosingBoundingBox();
}

bool FrameView::isScrollable()
{
    // Check for:
    // 1) If there an actual overflow.
    // 2) display:none or visibility:hidden set to self or inherited.
    // 3) overflow{-x,-y}: hidden;
    // 4) scrolling: no;

    // Covers #1
    IntSize contentsSize = this->contentsSize();
    IntSize visibleContentSize = visibleContentRect().size();
    if ((contentsSize.height() <= visibleContentSize.height() && contentsSize.width() <= visibleContentSize.width()))
        return false;

    // Covers #2.
    HTMLFrameOwnerElement* owner = m_frame->ownerElement();
    if (owner && (!owner->renderer() || !owner->renderer()->visibleToHitTesting()))
        return false;

    // Cover #3 and #4.
    ScrollbarMode horizontalMode;
    ScrollbarMode verticalMode;
    calculateScrollbarModesForLayoutAndSetViewportRenderer(horizontalMode, verticalMode, RulesFromWebContentOnly);
    if (horizontalMode == ScrollbarAlwaysOff && verticalMode == ScrollbarAlwaysOff)
        return false;

    return true;
}

void FrameView::updateScrollableAreaSet()
{
    // That ensures that only inner frames are cached.
    FrameView* parentFrameView = this->parentFrameView();
    if (!parentFrameView)
        return;

    if (!isScrollable()) {
        parentFrameView->removeScrollableArea(this);
        return;
    }

    parentFrameView->addScrollableArea(this);
}

bool FrameView::shouldSuspendScrollAnimations() const
{
    return m_frame->loader().state() != FrameStateComplete;
}

void FrameView::scrollbarStyleChanged(int newStyle, bool forceUpdate)
{
    if (!isMainFrame())
        return;

    if (forceUpdate)
        ScrollView::scrollbarStyleChanged(newStyle, forceUpdate);
}

void FrameView::notifyPageThatContentAreaWillPaint() const
{
    Page* page = m_frame->page();
    if (!page)
        return;

    contentAreaWillPaint();

    if (!m_scrollableAreas)
        return;

    for (HashSet<ScrollableArea*>::const_iterator it = m_scrollableAreas->begin(), end = m_scrollableAreas->end(); it != end; ++it) {
        ScrollableArea* scrollableArea = *it;

        if (!scrollableArea->scrollbarsCanBeActive())
            continue;

        scrollableArea->contentAreaWillPaint();
    }
}

bool FrameView::scrollAnimatorEnabled() const
{
    return m_frame->settings() && m_frame->settings()->scrollAnimatorEnabled();
}

void FrameView::updateAnnotatedRegions()
{
    Document* document = m_frame->document();
    if (!document->hasAnnotatedRegions())
        return;
    Vector<AnnotatedRegionValue> newRegions;
    document->renderBox()->collectAnnotatedRegions(newRegions);
    if (newRegions == document->annotatedRegions())
        return;
    document->setAnnotatedRegions(newRegions);
    if (Page* page = m_frame->page())
        page->chrome().client().annotatedRegionsChanged();
}

void FrameView::updateScrollCorner()
{
    RefPtr<RenderStyle> cornerStyle;
    IntRect cornerRect = scrollCornerRect();
    Document* doc = m_frame->document();

    if (doc && !cornerRect.isEmpty()) {
        // Try the <body> element first as a scroll corner source.
        if (Element* body = doc->body()) {
            if (RenderObject* renderer = body->renderer())
                cornerStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), renderer->style());
        }

        if (!cornerStyle) {
            // If the <body> didn't have a custom style, then the root element might.
            if (Element* docElement = doc->documentElement()) {
                if (RenderObject* renderer = docElement->renderer())
                    cornerStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), renderer->style());
            }
        }

        if (!cornerStyle) {
            // If we have an owning ipage/LocalFrame element, then it can set the custom scrollbar also.
            if (RenderPart* renderer = m_frame->ownerRenderer())
                cornerStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(SCROLLBAR_CORNER), renderer->style());
        }
    }

    if (cornerStyle) {
        if (!m_scrollCorner)
            m_scrollCorner = RenderScrollbarPart::createAnonymous(doc);
        m_scrollCorner->setStyle(cornerStyle.release());
        invalidateScrollCorner(cornerRect);
    } else if (m_scrollCorner) {
        m_scrollCorner->destroy();
        m_scrollCorner = 0;
    }

    ScrollView::updateScrollCorner();
}

void FrameView::paintScrollCorner(GraphicsContext* context, const IntRect& cornerRect)
{
    if (context->updatingControlTints()) {
        updateScrollCorner();
        return;
    }

    if (m_scrollCorner) {
        bool needsBackgorund = isMainFrame();
        if (needsBackgorund)
            context->fillRect(cornerRect, baseBackgroundColor());
        m_scrollCorner->paintIntoRect(context, cornerRect.location(), cornerRect);
        return;
    }

    ScrollView::paintScrollCorner(context, cornerRect);
}

void FrameView::paintScrollbar(GraphicsContext* context, Scrollbar* bar, const IntRect& rect)
{
    bool needsBackgorund = bar->isCustomScrollbar() && isMainFrame();
    if (needsBackgorund) {
        IntRect toFill = bar->frameRect();
        toFill.intersect(rect);
        context->fillRect(toFill, baseBackgroundColor());
    }

    ScrollView::paintScrollbar(context, bar, rect);
}

Color FrameView::documentBackgroundColor() const
{
    // <https://bugs.webkit.org/show_bug.cgi?id=59540> We blend the background color of
    // the document and the body against the base background color of the frame view.
    // Background images are unfortunately impractical to include.

    Color result = baseBackgroundColor();
    if (!frame().document())
        return result;

    Element* htmlElement = frame().document()->documentElement();
    Element* bodyElement = frame().document()->body();

    // We take the aggregate of the base background color
    // the <html> background color, and the <body>
    // background color to find the document color. The
    // addition of the base background color is not
    // technically part of the document background, but it
    // otherwise poses problems when the aggregate is not
    // fully opaque.
    if (htmlElement && htmlElement->renderer())
        result = result.blend(htmlElement->renderer()->style()->visitedDependentColor(CSSPropertyBackgroundColor));
    if (bodyElement && bodyElement->renderer())
        result = result.blend(bodyElement->renderer()->style()->visitedDependentColor(CSSPropertyBackgroundColor));

    return result;
}

bool FrameView::hasCustomScrollbars() const
{
    const HashSet<RefPtr<Widget> >* viewChildren = children();
    HashSet<RefPtr<Widget> >::const_iterator end = viewChildren->end();
    for (HashSet<RefPtr<Widget> >::const_iterator current = viewChildren->begin(); current != end; ++current) {
        Widget* widget = current->get();
        if (widget->isFrameView()) {
            if (toFrameView(widget)->hasCustomScrollbars())
                return true;
        } else if (widget->isScrollbar()) {
            Scrollbar* scrollbar = static_cast<Scrollbar*>(widget);
            if (scrollbar->isCustomScrollbar())
                return true;
        }
    }

    return false;
}

FrameView* FrameView::parentFrameView() const
{
    if (!parent())
        return 0;

    if (LocalFrame* parentFrame = m_frame->tree().parent())
        return parentFrame->view();

    return 0;
}

void FrameView::updateControlTints()
{
    // This is called when control tints are changed from aqua/graphite to clear and vice versa.
    // We do a "fake" paint, and when the theme gets a paint call, it can then do an invalidate.
    // This is only done if the theme supports control tinting. It's up to the theme and platform
    // to define when controls get the tint and to call this function when that changes.

    // Optimize the common case where we bring a window to the front while it's still empty.
    if (m_frame->document()->url().isEmpty())
        return;

    // FIXME: We shouldn't rely on the paint code to implement :window-inactive on custom scrollbars.
    if (!RenderTheme::theme().supportsControlTints() && !hasCustomScrollbars())
        return;

    // Updating layout can run script, which can tear down the FrameView.
    RefPtr<FrameView> protector(this);
    updateLayoutAndStyleForPainting();

    // FIXME: The use of paint seems like overkill: crbug.com/236892
    GraphicsContext context(0); // NULL canvas to get a non-painting context.
    context.setUpdatingControlTints(true);
    paint(&context, frameRect());
}

bool FrameView::wasScrolledByUser() const
{
    return m_wasScrolledByUser;
}

void FrameView::setWasScrolledByUser(bool wasScrolledByUser)
{
    if (m_inProgrammaticScroll)
        return;
    m_maintainScrollPositionAnchor = nullptr;
    m_wasScrolledByUser = wasScrolledByUser;
}

void FrameView::paintContents(GraphicsContext* p, const IntRect& rect)
{
    Document* document = m_frame->document();

#ifndef NDEBUG
    bool fillWithRed;
    if (document->printing())
        fillWithRed = false; // Printing, don't fill with red (can't remember why).
    else if (m_frame->ownerElement())
        fillWithRed = false; // Subframe, don't fill with red.
    else if (isTransparent())
        fillWithRed = false; // Transparent, don't fill with red.
    else if (m_paintBehavior & PaintBehaviorSelectionOnly)
        fillWithRed = false; // Selections are transparent, don't fill with red.
    else if (m_nodeToDraw)
        fillWithRed = false; // Element images are transparent, don't fill with red.
    else
        fillWithRed = true;

    if (fillWithRed)
        p->fillRect(rect, Color(0xFF, 0, 0));
#endif

    RenderView* renderView = this->renderView();
    if (!renderView) {
        WTF_LOG_ERROR("called FrameView::paint with nil renderer");
        return;
    }

    ASSERT(!needsLayout());
    if (needsLayout())
        return;

    InspectorInstrumentation::willPaint(renderView, 0);

    bool isTopLevelPainter = !s_inPaintContents;
    s_inPaintContents = true;

    FontCachePurgePreventer fontCachePurgePreventer;

    PaintBehavior oldPaintBehavior = m_paintBehavior;

    if (FrameView* parentView = parentFrameView()) {
        if (parentView->paintBehavior() & PaintBehaviorFlattenCompositingLayers)
            m_paintBehavior |= PaintBehaviorFlattenCompositingLayers;
    }

    if (m_paintBehavior == PaintBehaviorNormal)
        document->markers().invalidateRenderedRectsForMarkersInRect(rect);

    if (document->printing())
        m_paintBehavior |= PaintBehaviorFlattenCompositingLayers;

    ASSERT(!m_isPainting);
    m_isPainting = true;

    // m_nodeToDraw is used to draw only one element (and its descendants)
    RenderObject* renderer = m_nodeToDraw ? m_nodeToDraw->renderer() : 0;
    RenderLayer* rootLayer = renderView->layer();

#ifndef NDEBUG
    renderView->assertSubtreeIsLaidOut();
    RenderObject::SetLayoutNeededForbiddenScope forbidSetNeedsLayout(rootLayer->renderer());
#endif

    RenderObject* enclosingLayerRenderer = renderer ? renderer->enclosingLayer()->renderer() : 0;
    rootLayer->paint(p, rect, m_paintBehavior, enclosingLayerRenderer);

    if (rootLayer->containsDirtyOverlayScrollbars())
        rootLayer->paintOverlayScrollbars(p, rect, m_paintBehavior, renderer);

    m_isPainting = false;

    m_paintBehavior = oldPaintBehavior;
    m_lastPaintTime = currentTime();

    // Regions may have changed as a result of the visibility/z-index of element changing.
    if (document->annotatedRegionsDirty())
        updateAnnotatedRegions();

    if (isTopLevelPainter) {
        // Everythin that happens after paintContents completions is considered
        // to be part of the next frame.
        s_currentFrameTimeStamp = currentTime();
        s_inPaintContents = false;
    }

    InspectorInstrumentation::didPaint(renderView, 0, p, rect);
}

void FrameView::setPaintBehavior(PaintBehavior behavior)
{
    m_paintBehavior = behavior;
}

PaintBehavior FrameView::paintBehavior() const
{
    return m_paintBehavior;
}

bool FrameView::isPainting() const
{
    return m_isPainting;
}

void FrameView::setNodeToDraw(Node* node)
{
    m_nodeToDraw = node;
}

void FrameView::paintOverhangAreas(GraphicsContext* context, const IntRect& horizontalOverhangArea, const IntRect& verticalOverhangArea, const IntRect& dirtyRect)
{
    if (context->paintingDisabled())
        return;

    if (m_frame->document()->printing())
        return;

    if (isMainFrame()) {
        if (m_frame->page()->chrome().client().paintCustomOverhangArea(context, horizontalOverhangArea, verticalOverhangArea, dirtyRect))
            return;
    }

    ScrollView::paintOverhangAreas(context, horizontalOverhangArea, verticalOverhangArea, dirtyRect);
}

void FrameView::updateLayoutAndStyleForPainting()
{
    // Updating layout can run script, which can tear down the FrameView.
    RefPtr<FrameView> protector(this);

    updateLayoutAndStyleIfNeededRecursive();
    if (RenderView* view = renderView()) {
        ASSERT(!view->needsLayout());
        view->compositor()->updateCompositingLayers();

        // FIXME: we should not have any dirty bits left at this point. Unfortunately, this is not yet the case because
        // the code in updateCompositingLayers sometimes creates new dirty bits when updating direct compositing reasons.
        // See crbug.com/354100.
        view->compositor()->scheduleAnimationIfNeeded();
    }

    scrollContentsIfNeededRecursive();
}

void FrameView::updateLayoutAndStyleIfNeededRecursive()
{
    // We have to crawl our entire tree looking for any FrameViews that need
    // layout and make sure they are up to date.
    // Mac actually tests for intersection with the dirty region and tries not to
    // update layout for frames that are outside the dirty region.  Not only does this seem
    // pointless (since those frames will have set a zero timer to layout anyway), but
    // it is also incorrect, since if two frames overlap, the first could be excluded from the dirty
    // region but then become included later by the second frame adding rects to the dirty region
    // when it lays out.

    m_frame->document()->updateRenderTreeIfNeeded();

    if (needsLayout())
        layout();

    // FIXME: Calling layout() shouldn't trigger scripe execution or have any
    // observable effects on the frame tree but we're not quite there yet.
    Vector<RefPtr<FrameView> > frameViews;
    for (LocalFrame* child = m_frame->tree().firstChild(); child; child = child->tree().nextSibling()) {
        if (FrameView* view = child->view())
            frameViews.append(view);
    }

    const Vector<RefPtr<FrameView> >::iterator end = frameViews.end();
    for (Vector<RefPtr<FrameView> >::iterator it = frameViews.begin(); it != end; ++it)
        (*it)->updateLayoutAndStyleIfNeededRecursive();

    // This assert ensures that parent frames are clean, when child frames finished updating layout and style.
    ASSERT(!needsLayout());
}

void FrameView::enableAutoSizeMode(bool enable, const IntSize& minSize, const IntSize& maxSize)
{
    ASSERT(!enable || !minSize.isEmpty());
    ASSERT(minSize.width() <= maxSize.width());
    ASSERT(minSize.height() <= maxSize.height());

    if (m_shouldAutoSize == enable && m_minAutoSize == minSize && m_maxAutoSize == maxSize)
        return;


    m_shouldAutoSize = enable;
    m_minAutoSize = minSize;
    m_maxAutoSize = maxSize;
    m_didRunAutosize = false;

    setLayoutSizeFixedToFrameSize(enable);
    setNeedsLayout();
    scheduleRelayout();
    if (m_shouldAutoSize)
        return;

    // Since autosize mode forces the scrollbar mode, change them to being auto.
    setVerticalScrollbarLock(false);
    setHorizontalScrollbarLock(false);
    setScrollbarModes(ScrollbarAuto, ScrollbarAuto);
}

void FrameView::forceLayout(bool allowSubtree)
{
    layout(allowSubtree);
}

void FrameView::forceLayoutForPagination(const FloatSize& pageSize, const FloatSize& originalPageSize, float maximumShrinkFactor)
{
    // Dumping externalRepresentation(m_frame->renderer()).ascii() is a good trick to see
    // the state of things before and after the layout
    if (RenderView* renderView = this->renderView()) {
        float pageLogicalWidth = renderView->style()->isHorizontalWritingMode() ? pageSize.width() : pageSize.height();
        float pageLogicalHeight = renderView->style()->isHorizontalWritingMode() ? pageSize.height() : pageSize.width();

        LayoutUnit flooredPageLogicalWidth = static_cast<LayoutUnit>(pageLogicalWidth);
        LayoutUnit flooredPageLogicalHeight = static_cast<LayoutUnit>(pageLogicalHeight);
        renderView->setLogicalWidth(flooredPageLogicalWidth);
        renderView->setPageLogicalHeight(flooredPageLogicalHeight);
        renderView->setNeedsLayoutAndPrefWidthsRecalc();
        forceLayout();

        // If we don't fit in the given page width, we'll lay out again. If we don't fit in the
        // page width when shrunk, we will lay out at maximum shrink and clip extra content.
        // FIXME: We are assuming a shrink-to-fit printing implementation.  A cropping
        // implementation should not do this!
        bool horizontalWritingMode = renderView->style()->isHorizontalWritingMode();
        const LayoutRect& documentRect = renderView->documentRect();
        LayoutUnit docLogicalWidth = horizontalWritingMode ? documentRect.width() : documentRect.height();
        if (docLogicalWidth > pageLogicalWidth) {
            FloatSize expectedPageSize(std::min<float>(documentRect.width().toFloat(), pageSize.width() * maximumShrinkFactor), std::min<float>(documentRect.height().toFloat(), pageSize.height() * maximumShrinkFactor));
            FloatSize maxPageSize = m_frame->resizePageRectsKeepingRatio(FloatSize(originalPageSize.width(), originalPageSize.height()), expectedPageSize);
            pageLogicalWidth = horizontalWritingMode ? maxPageSize.width() : maxPageSize.height();
            pageLogicalHeight = horizontalWritingMode ? maxPageSize.height() : maxPageSize.width();

            flooredPageLogicalWidth = static_cast<LayoutUnit>(pageLogicalWidth);
            flooredPageLogicalHeight = static_cast<LayoutUnit>(pageLogicalHeight);
            renderView->setLogicalWidth(flooredPageLogicalWidth);
            renderView->setPageLogicalHeight(flooredPageLogicalHeight);
            renderView->setNeedsLayoutAndPrefWidthsRecalc();
            forceLayout();

            const LayoutRect& updatedDocumentRect = renderView->documentRect();
            LayoutUnit docLogicalHeight = horizontalWritingMode ? updatedDocumentRect.height() : updatedDocumentRect.width();
            LayoutUnit docLogicalTop = horizontalWritingMode ? updatedDocumentRect.y() : updatedDocumentRect.x();
            LayoutUnit docLogicalRight = horizontalWritingMode ? updatedDocumentRect.maxX() : updatedDocumentRect.maxY();
            LayoutUnit clippedLogicalLeft = 0;
            if (!renderView->style()->isLeftToRightDirection())
                clippedLogicalLeft = docLogicalRight - pageLogicalWidth;
            LayoutRect overflow(clippedLogicalLeft, docLogicalTop, pageLogicalWidth, docLogicalHeight);

            if (!horizontalWritingMode)
                overflow = overflow.transposedRect();
            renderView->clearLayoutOverflow();
            renderView->addLayoutOverflow(overflow); // This is how we clip in case we overflow again.
        }
    }

    adjustViewSize();
}

IntRect FrameView::convertFromRenderer(const RenderObject* renderer, const IntRect& rendererRect) const
{
    IntRect rect = pixelSnappedIntRect(enclosingLayoutRect(renderer->localToAbsoluteQuad(FloatRect(rendererRect)).boundingBox()));

    // Convert from page ("absolute") to FrameView coordinates.
    rect.moveBy(-scrollPosition());

    return rect;
}

IntRect FrameView::convertToRenderer(const RenderObject* renderer, const IntRect& viewRect) const
{
    IntRect rect = viewRect;

    // Convert from FrameView coords into page ("absolute") coordinates.
    rect.moveBy(scrollPosition());

    // FIXME: we don't have a way to map an absolute rect down to a local quad, so just
    // move the rect for now.
    rect.setLocation(roundedIntPoint(renderer->absoluteToLocal(rect.location(), UseTransforms)));
    return rect;
}

IntPoint FrameView::convertFromRenderer(const RenderObject* renderer, const IntPoint& rendererPoint) const
{
    IntPoint point = roundedIntPoint(renderer->localToAbsolute(rendererPoint, UseTransforms));

    // Convert from page ("absolute") to FrameView coordinates.
    point.moveBy(-scrollPosition());
    return point;
}

IntPoint FrameView::convertToRenderer(const RenderObject* renderer, const IntPoint& viewPoint) const
{
    IntPoint point = viewPoint;

    // Convert from FrameView coords into page ("absolute") coordinates.
    point += IntSize(scrollX(), scrollY());

    return roundedIntPoint(renderer->absoluteToLocal(point, UseTransforms));
}

IntRect FrameView::convertToContainingView(const IntRect& localRect) const
{
    if (const ScrollView* parentScrollView = toScrollView(parent())) {
        if (parentScrollView->isFrameView()) {
            const FrameView* parentView = toFrameView(parentScrollView);
            // Get our renderer in the parent view
            RenderPart* renderer = m_frame->ownerRenderer();
            if (!renderer)
                return localRect;

            IntRect rect(localRect);
            // Add borders and padding??
            rect.move(renderer->borderLeft() + renderer->paddingLeft(),
                renderer->borderTop() + renderer->paddingTop());
            return parentView->convertFromRenderer(renderer, rect);
        }

        return Widget::convertToContainingView(localRect);
    }

    return localRect;
}

IntRect FrameView::convertFromContainingView(const IntRect& parentRect) const
{
    if (const ScrollView* parentScrollView = toScrollView(parent())) {
        if (parentScrollView->isFrameView()) {
            const FrameView* parentView = toFrameView(parentScrollView);

            // Get our renderer in the parent view
            RenderPart* renderer = m_frame->ownerRenderer();
            if (!renderer)
                return parentRect;

            IntRect rect = parentView->convertToRenderer(renderer, parentRect);
            // Subtract borders and padding
            rect.move(-renderer->borderLeft() - renderer->paddingLeft(),
                      -renderer->borderTop() - renderer->paddingTop());
            return rect;
        }

        return Widget::convertFromContainingView(parentRect);
    }

    return parentRect;
}

IntPoint FrameView::convertToContainingView(const IntPoint& localPoint) const
{
    if (const ScrollView* parentScrollView = toScrollView(parent())) {
        if (parentScrollView->isFrameView()) {
            const FrameView* parentView = toFrameView(parentScrollView);

            // Get our renderer in the parent view
            RenderPart* renderer = m_frame->ownerRenderer();
            if (!renderer)
                return localPoint;

            IntPoint point(localPoint);

            // Add borders and padding
            point.move(renderer->borderLeft() + renderer->paddingLeft(),
                       renderer->borderTop() + renderer->paddingTop());
            return parentView->convertFromRenderer(renderer, point);
        }

        return Widget::convertToContainingView(localPoint);
    }

    return localPoint;
}

IntPoint FrameView::convertFromContainingView(const IntPoint& parentPoint) const
{
    if (const ScrollView* parentScrollView = toScrollView(parent())) {
        if (parentScrollView->isFrameView()) {
            const FrameView* parentView = toFrameView(parentScrollView);

            // Get our renderer in the parent view
            RenderPart* renderer = m_frame->ownerRenderer();
            if (!renderer)
                return parentPoint;

            IntPoint point = parentView->convertToRenderer(renderer, parentPoint);
            // Subtract borders and padding
            point.move(-renderer->borderLeft() - renderer->paddingLeft(),
                       -renderer->borderTop() - renderer->paddingTop());
            return point;
        }

        return Widget::convertFromContainingView(parentPoint);
    }

    return parentPoint;
}

void FrameView::setTracksRepaints(bool trackRepaints)
{
    if (trackRepaints == m_isTrackingRepaints)
        return;

    for (LocalFrame* frame = m_frame->tree().top(); frame; frame = frame->tree().traverseNext()) {
        if (RenderView* renderView = frame->contentRenderer())
            renderView->compositor()->setTracksRepaints(trackRepaints);
    }

    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("blink.invalidation"),
        "FrameView::setTracksRepaints", "enabled", trackRepaints);

    resetTrackedRepaints();
    m_isTrackingRepaints = trackRepaints;
}

void FrameView::resetTrackedRepaints()
{
    m_trackedRepaintRects.clear();
    if (RenderView* renderView = this->renderView())
        renderView->compositor()->resetTrackedRepaintRects();
}

String FrameView::trackedRepaintRectsAsText() const
{
    TextStream ts;
    if (!m_trackedRepaintRects.isEmpty()) {
        ts << "(repaint rects\n";
        for (size_t i = 0; i < m_trackedRepaintRects.size(); ++i)
            ts << "  (rect " << m_trackedRepaintRects[i].x() << " " << m_trackedRepaintRects[i].y() << " " << m_trackedRepaintRects[i].width() << " " << m_trackedRepaintRects[i].height() << ")\n";
        ts << ")\n";
    }
    return ts.release();
}

void FrameView::addResizerArea(RenderBox* resizerBox)
{
    if (!m_resizerAreas)
        m_resizerAreas = adoptPtr(new ResizerAreaSet);
    m_resizerAreas->add(resizerBox);
}

void FrameView::removeResizerArea(RenderBox* resizerBox)
{
    if (!m_resizerAreas)
        return;

    ResizerAreaSet::iterator it = m_resizerAreas->find(resizerBox);
    if (it != m_resizerAreas->end())
        m_resizerAreas->remove(it);
}

bool FrameView::addScrollableArea(ScrollableArea* scrollableArea)
{
    ASSERT(scrollableArea);
    if (!m_scrollableAreas)
        m_scrollableAreas = adoptPtr(new ScrollableAreaSet);
    return m_scrollableAreas->add(scrollableArea).isNewEntry;
}

bool FrameView::removeScrollableArea(ScrollableArea* scrollableArea)
{
    if (!m_scrollableAreas)
        return false;

    ScrollableAreaSet::iterator it = m_scrollableAreas->find(scrollableArea);
    if (it == m_scrollableAreas->end())
        return false;

    m_scrollableAreas->remove(it);
    return true;
}

bool FrameView::containsScrollableArea(const ScrollableArea* scrollableArea) const
{
    ASSERT(scrollableArea);
    if (!m_scrollableAreas || !scrollableArea)
        return false;
    return m_scrollableAreas->contains(const_cast<ScrollableArea*>(scrollableArea));
}

void FrameView::removeChild(Widget* widget)
{
    if (widget->isFrameView())
        removeScrollableArea(toFrameView(widget));

    ScrollView::removeChild(widget);
}

bool FrameView::wheelEvent(const PlatformWheelEvent& wheelEvent)
{
    // Note that to allow for rubber-band over-scroll behavior, even non-scrollable views
    // should handle wheel events.
#if !USE(RUBBER_BANDING)
    if (!isScrollable())
        return false;
#endif

    // We don't allow mouse wheeling to happen in a ScrollView that has had its scrollbars explicitly disabled.
    if (!canHaveScrollbars())
        return false;

    return ScrollableArea::handleWheelEvent(wheelEvent);
}

bool FrameView::isVerticalDocument() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return true;

    return renderView->style()->isHorizontalWritingMode();
}

bool FrameView::isFlippedDocument() const
{
    RenderView* renderView = this->renderView();
    if (!renderView)
        return false;

    return renderView->style()->isFlippedBlocksWritingMode();
}

AXObjectCache* FrameView::axObjectCache() const
{
    if (frame().document())
        return frame().document()->existingAXObjectCache();
    return 0;
}

void FrameView::setCursor(const Cursor& cursor)
{
    Page* page = frame().page();
    if (!page)
        return;
    page->chrome().setCursor(cursor);
}

bool FrameView::isMainFrame() const
{
    return m_frame->isMainFrame();
}

void FrameView::frameRectsChanged()
{
    if (layoutSizeFixedToFrameSize())
        setLayoutSizeInternal(frameRect().size());

    ScrollView::frameRectsChanged();
}

void FrameView::setLayoutSizeInternal(const IntSize& size)
{
    if (m_layoutSize == size)
        return;

    m_layoutSize = size;
    contentsResized();
}

void FrameView::didAddScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
{
    ScrollableArea::didAddScrollbar(scrollbar, orientation);
    if (AXObjectCache* cache = axObjectCache())
        cache->handleScrollbarUpdate(this);
}

void FrameView::willRemoveScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
{
    ScrollableArea::willRemoveScrollbar(scrollbar, orientation);
    if (AXObjectCache* cache = axObjectCache()) {
        cache->remove(scrollbar);
        cache->handleScrollbarUpdate(this);
    }
}

} // namespace WebCore