Source/core/editing/EditingStyle.cpp

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This source file includes following definitions.
textDecorationPropertyForEditing
allEditingProperties
inheritableEditingProperties
copyEditingProperties
isEditingProperty
editingStyleFromComputedStyle
create
matches
hasAttribute
propertyExistsInStyle
m_tagName
m_tagName
m_tagName
valueIsPresentInStyle
addToStyle
create
propertyExistsInStyle
valueIsPresentInStyle
create
create
matches
hasAttribute
attributeName
m_attrName
m_attrName
valueIsPresentInStyle
addToStyle
attributeValueAsCSSValue
create
attributeValueAsCSSValue
m_fontSizeDelta
m_fontSizeDelta
m_fontSizeDelta
m_fontSizeDelta
m_fontSizeDelta
cssValueToRGBA
getRGBAFontColor
getRGBAFontColor
getRGBABackgroundColor
getRGBABackgroundColor
rgbaBackgroundColorInEffect
textAlignResolvingStartAndEnd
textAlignResolvingStartAndEnd
init
removeTextFillAndStrokeColorsIfNeeded
setProperty
replaceFontSizeByKeywordIfPossible
extractFontSizeDelta
isEmpty
textDirection
overrideWithStyle
clear
copy
extractAndRemoveBlockProperties
extractAndRemoveTextDirection
removeBlockProperties
removeStyleAddedByNode
removeStyleConflictingWithStyleOfNode
collapseTextDecorationProperties
triStateOfStyle
triStateOfStyle
triStateOfStyle
conflictsWithInlineStyleOfElement
htmlElementEquivalents
conflictsWithImplicitStyleOfElement
htmlAttributeEquivalents
conflictsWithImplicitStyleOfAttributes
extractConflictingImplicitStyleOfAttributes
styleIsPresentInComputedStyleOfNode
elementIsStyledSpanOrHTMLEquivalent
prepareToApplyAt
mergeTypingStyle
mergeInlineStyleOfElement
elementMatchesAndPropertyIsNotInInlineStyleDecl
extractEditingProperties
mergeInlineAndImplicitStyleOfElement
wrappingStyleForSerialization
mergeTextDecorationValues
mergeStyle
styleFromMatchedRulesForElement
mergeStyleFromRules
mergeStyleFromRulesForSerialization
removePropertiesInStyle
removeStyleFromRulesAndContext
removePropertiesInElementDefaultStyle
forceInline
legacyFontSize
styleAtSelectionStart
textDirectionForSelection
reconcileTextDecorationProperties
m_applySuperscript
setTextDecorationProperty
extractTextStyles
diffTextDecorations
fontWeightIsBold
fontWeightNeedsResolving
getPropertiesNotIn
getIdentifierValue
getIdentifierValue
isCSSValueLength
legacyFontSizeFromCSSValue
isTransparentColorValue
hasTransparentBackgroundColor
hasTransparentBackgroundColor
backgroundColorInEffect
/*
 * Copyright (C) 2007, 2008, 2009 Apple Computer, Inc.
 * Copyright (C) 2010, 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "core/editing/EditingStyle.h"

#include "HTMLNames.h"
#include "bindings/v8/ExceptionStatePlaceholder.h"
#include "core/css/CSSComputedStyleDeclaration.h"
#include "core/css/parser/BisonCSSParser.h"
#include "core/css/CSSRuleList.h"
#include "core/css/CSSStyleRule.h"
#include "core/css/CSSValueList.h"
#include "core/css/FontSize.h"
#include "core/css/RuntimeCSSEnabled.h"
#include "core/css/StylePropertySet.h"
#include "core/css/StyleRule.h"
#include "core/css/resolver/StyleResolver.h"
#include "core/dom/Element.h"
#include "core/dom/Node.h"
#include "core/dom/NodeTraversal.h"
#include "core/dom/Position.h"
#include "core/dom/QualifiedName.h"
#include "core/editing/ApplyStyleCommand.h"
#include "core/editing/Editor.h"
#include "core/editing/FrameSelection.h"
#include "core/editing/HTMLInterchange.h"
#include "core/editing/htmlediting.h"
#include "core/frame/LocalFrame.h"
#include "core/html/HTMLFontElement.h"
#include "core/rendering/style/RenderStyle.h"

namespace WebCore {

static const CSSPropertyID& textDecorationPropertyForEditing()
{
    static const CSSPropertyID property = RuntimeEnabledFeatures::css3TextDecorationsEnabled() ? CSSPropertyTextDecorationLine : CSSPropertyTextDecoration;
    return property;
}

// Editing style properties must be preserved during editing operation.
// e.g. when a user inserts a new paragraph, all properties listed here must be copied to the new paragraph.
// NOTE: Use either allEditingProperties() or inheritableEditingProperties() to
// respect runtime enabling of properties.
static const CSSPropertyID staticEditingProperties[] = {
    CSSPropertyBackgroundColor,
    CSSPropertyColor,
    CSSPropertyFontFamily,
    CSSPropertyFontSize,
    CSSPropertyFontStyle,
    CSSPropertyFontVariant,
    CSSPropertyFontWeight,
    CSSPropertyLetterSpacing,
    CSSPropertyLineHeight,
    CSSPropertyOrphans,
    CSSPropertyTextAlign,
    // FIXME: CSSPropertyTextDecoration needs to be removed when CSS3 Text
    // Decoration feature is no longer experimental.
    CSSPropertyTextDecoration,
    CSSPropertyTextDecorationLine,
    CSSPropertyTextIndent,
    CSSPropertyTextTransform,
    CSSPropertyWhiteSpace,
    CSSPropertyWidows,
    CSSPropertyWordSpacing,
    CSSPropertyWebkitTextDecorationsInEffect,
    CSSPropertyWebkitTextFillColor,
    CSSPropertyWebkitTextStrokeColor,
    CSSPropertyWebkitTextStrokeWidth,
};

enum EditingPropertiesType { OnlyInheritableEditingProperties, AllEditingProperties };

static const Vector<CSSPropertyID>& allEditingProperties()
{
    DEFINE_STATIC_LOCAL(Vector<CSSPropertyID>, properties, ());
    if (properties.isEmpty()) {
        RuntimeCSSEnabled::filterEnabledCSSPropertiesIntoVector(staticEditingProperties, WTF_ARRAY_LENGTH(staticEditingProperties), properties);
        if (RuntimeEnabledFeatures::css3TextDecorationsEnabled())
            properties.remove(properties.find(CSSPropertyTextDecoration));
    }
    return properties;
}

static const Vector<CSSPropertyID>& inheritableEditingProperties()
{
    DEFINE_STATIC_LOCAL(Vector<CSSPropertyID>, properties, ());
    if (properties.isEmpty()) {
        RuntimeCSSEnabled::filterEnabledCSSPropertiesIntoVector(staticEditingProperties, WTF_ARRAY_LENGTH(staticEditingProperties), properties);
        for (size_t index = 0; index < properties.size();) {
            if (!CSSProperty::isInheritedProperty(properties[index])) {
                properties.remove(index);
                continue;
            }
            ++index;
        }
    }
    return properties;
}

template <class StyleDeclarationType>
static PassRefPtrWillBeRawPtr<MutableStylePropertySet> copyEditingProperties(StyleDeclarationType* style, EditingPropertiesType type = OnlyInheritableEditingProperties)
{
    if (type == AllEditingProperties)
        return style->copyPropertiesInSet(allEditingProperties());
    return style->copyPropertiesInSet(inheritableEditingProperties());
}

static inline bool isEditingProperty(int id)
{
    return allEditingProperties().contains(static_cast<CSSPropertyID>(id));
}

static PassRefPtrWillBeRawPtr<MutableStylePropertySet> editingStyleFromComputedStyle(PassRefPtr<CSSComputedStyleDeclaration> style, EditingPropertiesType type = OnlyInheritableEditingProperties)
{
    if (!style)
        return MutableStylePropertySet::create();
    return copyEditingProperties(style.get(), type);
}

static PassRefPtrWillBeRawPtr<MutableStylePropertySet> getPropertiesNotIn(StylePropertySet* styleWithRedundantProperties, CSSStyleDeclaration* baseStyle);
enum LegacyFontSizeMode { AlwaysUseLegacyFontSize, UseLegacyFontSizeOnlyIfPixelValuesMatch };
static int legacyFontSizeFromCSSValue(Document*, CSSPrimitiveValue*, bool shouldUseFixedFontDefaultSize, LegacyFontSizeMode);
static bool isTransparentColorValue(CSSValue*);
static bool hasTransparentBackgroundColor(CSSStyleDeclaration*);
static bool hasTransparentBackgroundColor(StylePropertySet*);
static PassRefPtrWillBeRawPtr<CSSValue> backgroundColorInEffect(Node*);

class HTMLElementEquivalent {
    WTF_MAKE_FAST_ALLOCATED;
public:
    static PassOwnPtr<HTMLElementEquivalent> create(CSSPropertyID propertyID, CSSValueID primitiveValue, const QualifiedName& tagName)
    {
        return adoptPtr(new HTMLElementEquivalent(propertyID, primitiveValue, tagName));
    }

    virtual ~HTMLElementEquivalent() { }
    virtual bool matches(const Element* element) const { return !m_tagName || element->hasTagName(*m_tagName); }
    virtual bool hasAttribute() const { return false; }
    virtual bool propertyExistsInStyle(const StylePropertySet* style) const { return style->getPropertyCSSValue(m_propertyID); }
    virtual bool valueIsPresentInStyle(Element*, StylePropertySet*) const;
    virtual void addToStyle(Element*, EditingStyle*) const;

protected:
    HTMLElementEquivalent(CSSPropertyID);
    HTMLElementEquivalent(CSSPropertyID, const QualifiedName& tagName);
    HTMLElementEquivalent(CSSPropertyID, CSSValueID primitiveValue, const QualifiedName& tagName);
    const CSSPropertyID m_propertyID;
    const RefPtrWillBePersistent<CSSPrimitiveValue> m_primitiveValue;
    const QualifiedName* m_tagName; // We can store a pointer because HTML tag names are const global.
};

HTMLElementEquivalent::HTMLElementEquivalent(CSSPropertyID id)
    : m_propertyID(id)
    , m_tagName(0)
{
}

HTMLElementEquivalent::HTMLElementEquivalent(CSSPropertyID id, const QualifiedName& tagName)
    : m_propertyID(id)
    , m_tagName(&tagName)
{
}

HTMLElementEquivalent::HTMLElementEquivalent(CSSPropertyID id, CSSValueID primitiveValue, const QualifiedName& tagName)
    : m_propertyID(id)
    , m_primitiveValue(CSSPrimitiveValue::createIdentifier(primitiveValue))
    , m_tagName(&tagName)
{
    ASSERT(primitiveValue != CSSValueInvalid);
}

bool HTMLElementEquivalent::valueIsPresentInStyle(Element* element, StylePropertySet* style) const
{
    RefPtrWillBeRawPtr<CSSValue> value = style->getPropertyCSSValue(m_propertyID);
    return matches(element) && value && value->isPrimitiveValue() && toCSSPrimitiveValue(value.get())->getValueID() == m_primitiveValue->getValueID();
}

void HTMLElementEquivalent::addToStyle(Element*, EditingStyle* style) const
{
    style->setProperty(m_propertyID, m_primitiveValue->cssText());
}

class HTMLTextDecorationEquivalent : public HTMLElementEquivalent {
public:
    static PassOwnPtr<HTMLElementEquivalent> create(CSSValueID primitiveValue, const QualifiedName& tagName)
    {
        return adoptPtr(new HTMLTextDecorationEquivalent(primitiveValue, tagName));
    }
    virtual bool propertyExistsInStyle(const StylePropertySet*) const OVERRIDE;
    virtual bool valueIsPresentInStyle(Element*, StylePropertySet*) const OVERRIDE;

private:
    HTMLTextDecorationEquivalent(CSSValueID primitiveValue, const QualifiedName& tagName);
};

HTMLTextDecorationEquivalent::HTMLTextDecorationEquivalent(CSSValueID primitiveValue, const QualifiedName& tagName)
    : HTMLElementEquivalent(textDecorationPropertyForEditing(), primitiveValue, tagName)
    // m_propertyID is used in HTMLElementEquivalent::addToStyle
{
}

bool HTMLTextDecorationEquivalent::propertyExistsInStyle(const StylePropertySet* style) const
{
    return style->getPropertyCSSValue(CSSPropertyWebkitTextDecorationsInEffect)
        || style->getPropertyCSSValue(textDecorationPropertyForEditing());
}

bool HTMLTextDecorationEquivalent::valueIsPresentInStyle(Element* element, StylePropertySet* style) const
{
    RefPtrWillBeRawPtr<CSSValue> styleValue = style->getPropertyCSSValue(CSSPropertyWebkitTextDecorationsInEffect);
    if (!styleValue)
        styleValue = style->getPropertyCSSValue(textDecorationPropertyForEditing());
    return matches(element) && styleValue && styleValue->isValueList() && toCSSValueList(styleValue.get())->hasValue(m_primitiveValue.get());
}

class HTMLAttributeEquivalent : public HTMLElementEquivalent {
public:
    static PassOwnPtr<HTMLAttributeEquivalent> create(CSSPropertyID propertyID, const QualifiedName& tagName, const QualifiedName& attrName)
    {
        return adoptPtr(new HTMLAttributeEquivalent(propertyID, tagName, attrName));
    }
    static PassOwnPtr<HTMLAttributeEquivalent> create(CSSPropertyID propertyID, const QualifiedName& attrName)
    {
        return adoptPtr(new HTMLAttributeEquivalent(propertyID, attrName));
    }

    virtual bool matches(const Element* elem) const OVERRIDE { return HTMLElementEquivalent::matches(elem) && elem->hasAttribute(m_attrName); }
    virtual bool hasAttribute() const OVERRIDE { return true; }
    virtual bool valueIsPresentInStyle(Element*, StylePropertySet*) const OVERRIDE;
    virtual void addToStyle(Element*, EditingStyle*) const OVERRIDE;
    virtual PassRefPtrWillBeRawPtr<CSSValue> attributeValueAsCSSValue(Element*) const;
    inline const QualifiedName& attributeName() const { return m_attrName; }

protected:
    HTMLAttributeEquivalent(CSSPropertyID, const QualifiedName& tagName, const QualifiedName& attrName);
    HTMLAttributeEquivalent(CSSPropertyID, const QualifiedName& attrName);
    const QualifiedName& m_attrName; // We can store a reference because HTML attribute names are const global.
};

HTMLAttributeEquivalent::HTMLAttributeEquivalent(CSSPropertyID id, const QualifiedName& tagName, const QualifiedName& attrName)
    : HTMLElementEquivalent(id, tagName)
    , m_attrName(attrName)
{
}

HTMLAttributeEquivalent::HTMLAttributeEquivalent(CSSPropertyID id, const QualifiedName& attrName)
    : HTMLElementEquivalent(id)
    , m_attrName(attrName)
{
}

bool HTMLAttributeEquivalent::valueIsPresentInStyle(Element* element, StylePropertySet* style) const
{
    RefPtrWillBeRawPtr<CSSValue> value = attributeValueAsCSSValue(element);
    RefPtrWillBeRawPtr<CSSValue> styleValue = style->getPropertyCSSValue(m_propertyID);

    return compareCSSValuePtr(value, styleValue);
}

void HTMLAttributeEquivalent::addToStyle(Element* element, EditingStyle* style) const
{
    if (RefPtrWillBeRawPtr<CSSValue> value = attributeValueAsCSSValue(element))
        style->setProperty(m_propertyID, value->cssText());
}

PassRefPtrWillBeRawPtr<CSSValue> HTMLAttributeEquivalent::attributeValueAsCSSValue(Element* element) const
{
    ASSERT(element);
    const AtomicString& value = element->getAttribute(m_attrName);
    if (value.isNull())
        return nullptr;

    RefPtrWillBeRawPtr<MutableStylePropertySet> dummyStyle = nullptr;
    dummyStyle = MutableStylePropertySet::create();
    dummyStyle->setProperty(m_propertyID, value);
    return dummyStyle->getPropertyCSSValue(m_propertyID);
}

class HTMLFontSizeEquivalent FINAL : public HTMLAttributeEquivalent {
public:
    static PassOwnPtr<HTMLFontSizeEquivalent> create()
    {
        return adoptPtr(new HTMLFontSizeEquivalent());
    }
    virtual PassRefPtrWillBeRawPtr<CSSValue> attributeValueAsCSSValue(Element*) const OVERRIDE;

private:
    HTMLFontSizeEquivalent();
};

HTMLFontSizeEquivalent::HTMLFontSizeEquivalent()
    : HTMLAttributeEquivalent(CSSPropertyFontSize, HTMLNames::fontTag, HTMLNames::sizeAttr)
{
}

PassRefPtrWillBeRawPtr<CSSValue> HTMLFontSizeEquivalent::attributeValueAsCSSValue(Element* element) const
{
    ASSERT(element);
    const AtomicString& value = element->getAttribute(m_attrName);
    if (value.isNull())
        return nullptr;
    CSSValueID size;
    if (!HTMLFontElement::cssValueFromFontSizeNumber(value, size))
        return nullptr;
    return CSSPrimitiveValue::createIdentifier(size);
}

float EditingStyle::NoFontDelta = 0.0f;

EditingStyle::EditingStyle()
    : m_shouldUseFixedDefaultFontSize(false)
    , m_fontSizeDelta(NoFontDelta)
{
}

EditingStyle::EditingStyle(Node* node, PropertiesToInclude propertiesToInclude)
    : m_shouldUseFixedDefaultFontSize(false)
    , m_fontSizeDelta(NoFontDelta)
{
    init(node, propertiesToInclude);
}

EditingStyle::EditingStyle(const Position& position, PropertiesToInclude propertiesToInclude)
    : m_shouldUseFixedDefaultFontSize(false)
    , m_fontSizeDelta(NoFontDelta)
{
    init(position.deprecatedNode(), propertiesToInclude);
}

EditingStyle::EditingStyle(const StylePropertySet* style)
    : m_mutableStyle(style ? style->mutableCopy() : nullptr)
    , m_shouldUseFixedDefaultFontSize(false)
    , m_fontSizeDelta(NoFontDelta)
{
    extractFontSizeDelta();
}

EditingStyle::EditingStyle(CSSPropertyID propertyID, const String& value)
    : m_mutableStyle(nullptr)
    , m_shouldUseFixedDefaultFontSize(false)
    , m_fontSizeDelta(NoFontDelta)
{
    setProperty(propertyID, value);
}

EditingStyle::~EditingStyle()
{
}

static RGBA32 cssValueToRGBA(CSSValue* colorValue)
{
    if (!colorValue || !colorValue->isPrimitiveValue())
        return Color::transparent;

    CSSPrimitiveValue* primitiveColor = toCSSPrimitiveValue(colorValue);
    if (primitiveColor->isRGBColor())
        return primitiveColor->getRGBA32Value();

    RGBA32 rgba = 0;
    BisonCSSParser::parseColor(rgba, colorValue->cssText());
    return rgba;
}

static inline RGBA32 getRGBAFontColor(CSSStyleDeclaration* style)
{
    return cssValueToRGBA(style->getPropertyCSSValueInternal(CSSPropertyColor).get());
}

static inline RGBA32 getRGBAFontColor(StylePropertySet* style)
{
    return cssValueToRGBA(style->getPropertyCSSValue(CSSPropertyColor).get());
}

static inline RGBA32 getRGBABackgroundColor(CSSStyleDeclaration* style)
{
    return cssValueToRGBA(style->getPropertyCSSValueInternal(CSSPropertyBackgroundColor).get());
}

static inline RGBA32 getRGBABackgroundColor(StylePropertySet* style)
{
    return cssValueToRGBA(style->getPropertyCSSValue(CSSPropertyBackgroundColor).get());
}

static inline RGBA32 rgbaBackgroundColorInEffect(Node* node)
{
    return cssValueToRGBA(backgroundColorInEffect(node).get());
}

static int textAlignResolvingStartAndEnd(int textAlign, int direction)
{
    switch (textAlign) {
    case CSSValueCenter:
    case CSSValueWebkitCenter:
        return CSSValueCenter;
    case CSSValueJustify:
        return CSSValueJustify;
    case CSSValueLeft:
    case CSSValueWebkitLeft:
        return CSSValueLeft;
    case CSSValueRight:
    case CSSValueWebkitRight:
        return CSSValueRight;
    case CSSValueStart:
        return direction != CSSValueRtl ? CSSValueLeft : CSSValueRight;
    case CSSValueEnd:
        return direction == CSSValueRtl ? CSSValueRight : CSSValueLeft;
    }
    return CSSValueInvalid;
}

template<typename T>
static int textAlignResolvingStartAndEnd(T* style)
{
    return textAlignResolvingStartAndEnd(getIdentifierValue(style, CSSPropertyTextAlign), getIdentifierValue(style, CSSPropertyDirection));
}

void EditingStyle::init(Node* node, PropertiesToInclude propertiesToInclude)
{
    if (isTabSpanTextNode(node))
        node = tabSpanNode(node)->parentNode();
    else if (isTabSpanNode(node))
        node = node->parentNode();

    RefPtr<CSSComputedStyleDeclaration> computedStyleAtPosition = CSSComputedStyleDeclaration::create(node);
    m_mutableStyle = propertiesToInclude == AllProperties && computedStyleAtPosition ? computedStyleAtPosition->copyProperties() : editingStyleFromComputedStyle(computedStyleAtPosition);

    if (propertiesToInclude == EditingPropertiesInEffect) {
        if (RefPtrWillBeRawPtr<CSSValue> value = backgroundColorInEffect(node))
            m_mutableStyle->setProperty(CSSPropertyBackgroundColor, value->cssText());
        if (RefPtrWillBeRawPtr<CSSValue> value = computedStyleAtPosition->getPropertyCSSValue(CSSPropertyWebkitTextDecorationsInEffect))
            m_mutableStyle->setProperty(CSSPropertyTextDecoration, value->cssText());
    }

    if (node && node->computedStyle()) {
        RenderStyle* renderStyle = node->computedStyle();
        removeTextFillAndStrokeColorsIfNeeded(renderStyle);
        replaceFontSizeByKeywordIfPossible(renderStyle, computedStyleAtPosition.get());
    }

    m_shouldUseFixedDefaultFontSize = computedStyleAtPosition->useFixedFontDefaultSize();
    extractFontSizeDelta();
}

void EditingStyle::removeTextFillAndStrokeColorsIfNeeded(RenderStyle* renderStyle)
{
    // If a node's text fill color is currentColor, then its children use
    // their font-color as their text fill color (they don't
    // inherit it).  Likewise for stroke color.
    if (renderStyle->textFillColor().isCurrentColor())
        m_mutableStyle->removeProperty(CSSPropertyWebkitTextFillColor);
    if (renderStyle->textStrokeColor().isCurrentColor())
        m_mutableStyle->removeProperty(CSSPropertyWebkitTextStrokeColor);
}

void EditingStyle::setProperty(CSSPropertyID propertyID, const String& value, bool important)
{
    if (!m_mutableStyle)
        m_mutableStyle = MutableStylePropertySet::create();

    m_mutableStyle->setProperty(propertyID, value, important);
}

void EditingStyle::replaceFontSizeByKeywordIfPossible(RenderStyle* renderStyle, CSSComputedStyleDeclaration* computedStyle)
{
    ASSERT(renderStyle);
    if (renderStyle->fontDescription().keywordSize())
        m_mutableStyle->setProperty(CSSPropertyFontSize, computedStyle->getFontSizeCSSValuePreferringKeyword()->cssText());
}

void EditingStyle::extractFontSizeDelta()
{
    if (!m_mutableStyle)
        return;

    if (m_mutableStyle->getPropertyCSSValue(CSSPropertyFontSize)) {
        // Explicit font size overrides any delta.
        m_mutableStyle->removeProperty(CSSPropertyWebkitFontSizeDelta);
        return;
    }

    // Get the adjustment amount out of the style.
    RefPtrWillBeRawPtr<CSSValue> value = m_mutableStyle->getPropertyCSSValue(CSSPropertyWebkitFontSizeDelta);
    if (!value || !value->isPrimitiveValue())
        return;

    CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value.get());

    // Only PX handled now. If we handle more types in the future, perhaps
    // a switch statement here would be more appropriate.
    if (!primitiveValue->isPx())
        return;

    m_fontSizeDelta = primitiveValue->getFloatValue();
    m_mutableStyle->removeProperty(CSSPropertyWebkitFontSizeDelta);
}

bool EditingStyle::isEmpty() const
{
    return (!m_mutableStyle || m_mutableStyle->isEmpty()) && m_fontSizeDelta == NoFontDelta;
}

bool EditingStyle::textDirection(WritingDirection& writingDirection) const
{
    if (!m_mutableStyle)
        return false;

    RefPtrWillBeRawPtr<CSSValue> unicodeBidi = m_mutableStyle->getPropertyCSSValue(CSSPropertyUnicodeBidi);
    if (!unicodeBidi || !unicodeBidi->isPrimitiveValue())
        return false;

    CSSValueID unicodeBidiValue = toCSSPrimitiveValue(unicodeBidi.get())->getValueID();
    if (unicodeBidiValue == CSSValueEmbed) {
        RefPtrWillBeRawPtr<CSSValue> direction = m_mutableStyle->getPropertyCSSValue(CSSPropertyDirection);
        if (!direction || !direction->isPrimitiveValue())
            return false;

        writingDirection = toCSSPrimitiveValue(direction.get())->getValueID() == CSSValueLtr ? LeftToRightWritingDirection : RightToLeftWritingDirection;

        return true;
    }

    if (unicodeBidiValue == CSSValueNormal) {
        writingDirection = NaturalWritingDirection;
        return true;
    }

    return false;
}

void EditingStyle::overrideWithStyle(const StylePropertySet* style)
{
    if (!style || style->isEmpty())
        return;
    if (!m_mutableStyle)
        m_mutableStyle = MutableStylePropertySet::create();
    m_mutableStyle->mergeAndOverrideOnConflict(style);
    extractFontSizeDelta();
}

void EditingStyle::clear()
{
    m_mutableStyle.clear();
    m_shouldUseFixedDefaultFontSize = false;
    m_fontSizeDelta = NoFontDelta;
}

PassRefPtr<EditingStyle> EditingStyle::copy() const
{
    RefPtr<EditingStyle> copy = EditingStyle::create();
    if (m_mutableStyle)
        copy->m_mutableStyle = m_mutableStyle->mutableCopy();
    copy->m_shouldUseFixedDefaultFontSize = m_shouldUseFixedDefaultFontSize;
    copy->m_fontSizeDelta = m_fontSizeDelta;
    return copy;
}

PassRefPtr<EditingStyle> EditingStyle::extractAndRemoveBlockProperties()
{
    RefPtr<EditingStyle> blockProperties = EditingStyle::create();
    if (!m_mutableStyle)
        return blockProperties;

    blockProperties->m_mutableStyle = m_mutableStyle->copyBlockProperties();
    m_mutableStyle->removeBlockProperties();

    return blockProperties;
}

PassRefPtr<EditingStyle> EditingStyle::extractAndRemoveTextDirection()
{
    RefPtr<EditingStyle> textDirection = EditingStyle::create();
    textDirection->m_mutableStyle = MutableStylePropertySet::create();
    textDirection->m_mutableStyle->setProperty(CSSPropertyUnicodeBidi, CSSValueEmbed, m_mutableStyle->propertyIsImportant(CSSPropertyUnicodeBidi));
    textDirection->m_mutableStyle->setProperty(CSSPropertyDirection, m_mutableStyle->getPropertyValue(CSSPropertyDirection),
        m_mutableStyle->propertyIsImportant(CSSPropertyDirection));

    m_mutableStyle->removeProperty(CSSPropertyUnicodeBidi);
    m_mutableStyle->removeProperty(CSSPropertyDirection);

    return textDirection;
}

void EditingStyle::removeBlockProperties()
{
    if (!m_mutableStyle)
        return;

    m_mutableStyle->removeBlockProperties();
}

void EditingStyle::removeStyleAddedByNode(Node* node)
{
    if (!node || !node->parentNode())
        return;
    RefPtrWillBeRawPtr<MutableStylePropertySet> parentStyle = editingStyleFromComputedStyle(CSSComputedStyleDeclaration::create(node->parentNode()), AllEditingProperties);
    RefPtrWillBeRawPtr<MutableStylePropertySet> nodeStyle = editingStyleFromComputedStyle(CSSComputedStyleDeclaration::create(node), AllEditingProperties);
    nodeStyle->removeEquivalentProperties(parentStyle.get());
    m_mutableStyle->removeEquivalentProperties(nodeStyle.get());
}

void EditingStyle::removeStyleConflictingWithStyleOfNode(Node* node)
{
    if (!node || !node->parentNode() || !m_mutableStyle)
        return;

    RefPtrWillBeRawPtr<MutableStylePropertySet> parentStyle = editingStyleFromComputedStyle(CSSComputedStyleDeclaration::create(node->parentNode()), AllEditingProperties);
    RefPtrWillBeRawPtr<MutableStylePropertySet> nodeStyle = editingStyleFromComputedStyle(CSSComputedStyleDeclaration::create(node), AllEditingProperties);
    nodeStyle->removeEquivalentProperties(parentStyle.get());

    unsigned propertyCount = nodeStyle->propertyCount();
    for (unsigned i = 0; i < propertyCount; ++i)
        m_mutableStyle->removeProperty(nodeStyle->propertyAt(i).id());
}

void EditingStyle::collapseTextDecorationProperties()
{
    if (!m_mutableStyle)
        return;

    RefPtrWillBeRawPtr<CSSValue> textDecorationsInEffect = m_mutableStyle->getPropertyCSSValue(CSSPropertyWebkitTextDecorationsInEffect);
    if (!textDecorationsInEffect)
        return;

    if (textDecorationsInEffect->isValueList())
        m_mutableStyle->setProperty(textDecorationPropertyForEditing(), textDecorationsInEffect->cssText(), m_mutableStyle->propertyIsImportant(textDecorationPropertyForEditing()));
    else
        m_mutableStyle->removeProperty(textDecorationPropertyForEditing());
    m_mutableStyle->removeProperty(CSSPropertyWebkitTextDecorationsInEffect);
}

// CSS properties that create a visual difference only when applied to text.
static const CSSPropertyID textOnlyProperties[] = {
    // FIXME: CSSPropertyTextDecoration needs to be removed when CSS3 Text
    // Decoration feature is no longer experimental.
    CSSPropertyTextDecoration,
    CSSPropertyTextDecorationLine,
    CSSPropertyWebkitTextDecorationsInEffect,
    CSSPropertyFontStyle,
    CSSPropertyFontWeight,
    CSSPropertyColor,
};

TriState EditingStyle::triStateOfStyle(EditingStyle* style) const
{
    if (!style || !style->m_mutableStyle)
        return FalseTriState;
    return triStateOfStyle(style->m_mutableStyle->ensureCSSStyleDeclaration(), DoNotIgnoreTextOnlyProperties);
}

TriState EditingStyle::triStateOfStyle(CSSStyleDeclaration* styleToCompare, ShouldIgnoreTextOnlyProperties shouldIgnoreTextOnlyProperties) const
{
    RefPtrWillBeRawPtr<MutableStylePropertySet> difference = getPropertiesNotIn(m_mutableStyle.get(), styleToCompare);

    if (shouldIgnoreTextOnlyProperties == IgnoreTextOnlyProperties)
        difference->removePropertiesInSet(textOnlyProperties, WTF_ARRAY_LENGTH(textOnlyProperties));

    if (difference->isEmpty())
        return TrueTriState;
    if (difference->propertyCount() == m_mutableStyle->propertyCount())
        return FalseTriState;

    return MixedTriState;
}

TriState EditingStyle::triStateOfStyle(const VisibleSelection& selection) const
{
    if (!selection.isCaretOrRange())
        return FalseTriState;

    if (selection.isCaret())
        return triStateOfStyle(EditingStyle::styleAtSelectionStart(selection).get());

    TriState state = FalseTriState;
    bool nodeIsStart = true;
    for (Node* node = selection.start().deprecatedNode(); node; node = NodeTraversal::next(*node)) {
        if (node->renderer() && node->rendererIsEditable()) {
            RefPtr<CSSComputedStyleDeclaration> nodeStyle = CSSComputedStyleDeclaration::create(node);
            if (nodeStyle) {
                TriState nodeState = triStateOfStyle(nodeStyle.get(), node->isTextNode() ? EditingStyle::DoNotIgnoreTextOnlyProperties : EditingStyle::IgnoreTextOnlyProperties);
                if (nodeIsStart) {
                    state = nodeState;
                    nodeIsStart = false;
                } else if (state != nodeState && node->isTextNode()) {
                    state = MixedTriState;
                    break;
                }
            }
        }
        if (node == selection.end().deprecatedNode())
            break;
    }

    return state;
}

bool EditingStyle::conflictsWithInlineStyleOfElement(Element* element, EditingStyle* extractedStyle, Vector<CSSPropertyID>* conflictingProperties) const
{
    ASSERT(element);
    ASSERT(!conflictingProperties || conflictingProperties->isEmpty());

    const StylePropertySet* inlineStyle = element->inlineStyle();
    if (!m_mutableStyle || !inlineStyle)
        return false;

    unsigned propertyCount = m_mutableStyle->propertyCount();
    for (unsigned i = 0; i < propertyCount; ++i) {
        CSSPropertyID propertyID = m_mutableStyle->propertyAt(i).id();

        // We don't override whitespace property of a tab span because that would collapse the tab into a space.
        if (propertyID == CSSPropertyWhiteSpace && isTabSpanNode(element))
            continue;

        if (propertyID == CSSPropertyWebkitTextDecorationsInEffect && inlineStyle->getPropertyCSSValue(textDecorationPropertyForEditing())) {
            if (!conflictingProperties)
                return true;
            conflictingProperties->append(CSSPropertyTextDecoration);
            // Because text-decoration expands to text-decoration-line when CSS3
            // Text Decoration is enabled, we also state it as conflicting.
            if (RuntimeEnabledFeatures::css3TextDecorationsEnabled())
                conflictingProperties->append(CSSPropertyTextDecorationLine);
            if (extractedStyle)
                extractedStyle->setProperty(textDecorationPropertyForEditing(), inlineStyle->getPropertyValue(textDecorationPropertyForEditing()), inlineStyle->propertyIsImportant(textDecorationPropertyForEditing()));
            continue;
        }

        if (!inlineStyle->getPropertyCSSValue(propertyID))
            continue;

        if (propertyID == CSSPropertyUnicodeBidi && inlineStyle->getPropertyCSSValue(CSSPropertyDirection)) {
            if (!conflictingProperties)
                return true;
            conflictingProperties->append(CSSPropertyDirection);
            if (extractedStyle)
                extractedStyle->setProperty(propertyID, inlineStyle->getPropertyValue(propertyID), inlineStyle->propertyIsImportant(propertyID));
        }

        if (!conflictingProperties)
            return true;

        conflictingProperties->append(propertyID);

        if (extractedStyle)
            extractedStyle->setProperty(propertyID, inlineStyle->getPropertyValue(propertyID), inlineStyle->propertyIsImportant(propertyID));
    }

    return conflictingProperties && !conflictingProperties->isEmpty();
}

static const Vector<OwnPtr<HTMLElementEquivalent> >& htmlElementEquivalents()
{
    DEFINE_STATIC_LOCAL(Vector<OwnPtr<HTMLElementEquivalent> >, HTMLElementEquivalents, ());

    if (!HTMLElementEquivalents.size()) {
        HTMLElementEquivalents.append(HTMLElementEquivalent::create(CSSPropertyFontWeight, CSSValueBold, HTMLNames::bTag));
        HTMLElementEquivalents.append(HTMLElementEquivalent::create(CSSPropertyFontWeight, CSSValueBold, HTMLNames::strongTag));
        HTMLElementEquivalents.append(HTMLElementEquivalent::create(CSSPropertyVerticalAlign, CSSValueSub, HTMLNames::subTag));
        HTMLElementEquivalents.append(HTMLElementEquivalent::create(CSSPropertyVerticalAlign, CSSValueSuper, HTMLNames::supTag));
        HTMLElementEquivalents.append(HTMLElementEquivalent::create(CSSPropertyFontStyle, CSSValueItalic, HTMLNames::iTag));
        HTMLElementEquivalents.append(HTMLElementEquivalent::create(CSSPropertyFontStyle, CSSValueItalic, HTMLNames::emTag));

        HTMLElementEquivalents.append(HTMLTextDecorationEquivalent::create(CSSValueUnderline, HTMLNames::uTag));
        HTMLElementEquivalents.append(HTMLTextDecorationEquivalent::create(CSSValueLineThrough, HTMLNames::sTag));
        HTMLElementEquivalents.append(HTMLTextDecorationEquivalent::create(CSSValueLineThrough, HTMLNames::strikeTag));
    }

    return HTMLElementEquivalents;
}


bool EditingStyle::conflictsWithImplicitStyleOfElement(HTMLElement* element, EditingStyle* extractedStyle, ShouldExtractMatchingStyle shouldExtractMatchingStyle) const
{
    if (!m_mutableStyle)
        return false;

    const Vector<OwnPtr<HTMLElementEquivalent> >& HTMLElementEquivalents = htmlElementEquivalents();
    for (size_t i = 0; i < HTMLElementEquivalents.size(); ++i) {
        const HTMLElementEquivalent* equivalent = HTMLElementEquivalents[i].get();
        if (equivalent->matches(element) && equivalent->propertyExistsInStyle(m_mutableStyle.get())
            && (shouldExtractMatchingStyle == ExtractMatchingStyle || !equivalent->valueIsPresentInStyle(element, m_mutableStyle.get()))) {
            if (extractedStyle)
                equivalent->addToStyle(element, extractedStyle);
            return true;
        }
    }
    return false;
}

static const Vector<OwnPtr<HTMLAttributeEquivalent> >& htmlAttributeEquivalents()
{
    DEFINE_STATIC_LOCAL(Vector<OwnPtr<HTMLAttributeEquivalent> >, HTMLAttributeEquivalents, ());

    if (!HTMLAttributeEquivalents.size()) {
        // elementIsStyledSpanOrHTMLEquivalent depends on the fact each HTMLAttriuteEquivalent matches exactly one attribute
        // of exactly one element except dirAttr.
        HTMLAttributeEquivalents.append(HTMLAttributeEquivalent::create(CSSPropertyColor, HTMLNames::fontTag, HTMLNames::colorAttr));
        HTMLAttributeEquivalents.append(HTMLAttributeEquivalent::create(CSSPropertyFontFamily, HTMLNames::fontTag, HTMLNames::faceAttr));
        HTMLAttributeEquivalents.append(HTMLFontSizeEquivalent::create());

        HTMLAttributeEquivalents.append(HTMLAttributeEquivalent::create(CSSPropertyDirection, HTMLNames::dirAttr));
        HTMLAttributeEquivalents.append(HTMLAttributeEquivalent::create(CSSPropertyUnicodeBidi, HTMLNames::dirAttr));
    }

    return HTMLAttributeEquivalents;
}

bool EditingStyle::conflictsWithImplicitStyleOfAttributes(HTMLElement* element) const
{
    ASSERT(element);
    if (!m_mutableStyle)
        return false;

    const Vector<OwnPtr<HTMLAttributeEquivalent> >& HTMLAttributeEquivalents = htmlAttributeEquivalents();
    for (size_t i = 0; i < HTMLAttributeEquivalents.size(); ++i) {
        if (HTMLAttributeEquivalents[i]->matches(element) && HTMLAttributeEquivalents[i]->propertyExistsInStyle(m_mutableStyle.get())
            && !HTMLAttributeEquivalents[i]->valueIsPresentInStyle(element, m_mutableStyle.get()))
            return true;
    }

    return false;
}

bool EditingStyle::extractConflictingImplicitStyleOfAttributes(HTMLElement* element, ShouldPreserveWritingDirection shouldPreserveWritingDirection,
    EditingStyle* extractedStyle, Vector<QualifiedName>& conflictingAttributes, ShouldExtractMatchingStyle shouldExtractMatchingStyle) const
{
    ASSERT(element);
    // HTMLAttributeEquivalent::addToStyle doesn't support unicode-bidi and direction properties
    ASSERT(!extractedStyle || shouldPreserveWritingDirection == PreserveWritingDirection);
    if (!m_mutableStyle)
        return false;

    const Vector<OwnPtr<HTMLAttributeEquivalent> >& HTMLAttributeEquivalents = htmlAttributeEquivalents();
    bool removed = false;
    for (size_t i = 0; i < HTMLAttributeEquivalents.size(); ++i) {
        const HTMLAttributeEquivalent* equivalent = HTMLAttributeEquivalents[i].get();

        // unicode-bidi and direction are pushed down separately so don't push down with other styles.
        if (shouldPreserveWritingDirection == PreserveWritingDirection && equivalent->attributeName() == HTMLNames::dirAttr)
            continue;

        if (!equivalent->matches(element) || !equivalent->propertyExistsInStyle(m_mutableStyle.get())
            || (shouldExtractMatchingStyle == DoNotExtractMatchingStyle && equivalent->valueIsPresentInStyle(element, m_mutableStyle.get())))
            continue;

        if (extractedStyle)
            equivalent->addToStyle(element, extractedStyle);
        conflictingAttributes.append(equivalent->attributeName());
        removed = true;
    }

    return removed;
}

bool EditingStyle::styleIsPresentInComputedStyleOfNode(Node* node) const
{
    return !m_mutableStyle || getPropertiesNotIn(m_mutableStyle.get(), CSSComputedStyleDeclaration::create(node).get())->isEmpty();
}

bool EditingStyle::elementIsStyledSpanOrHTMLEquivalent(const HTMLElement* element)
{
    ASSERT(element);
    bool elementIsSpanOrElementEquivalent = false;
    if (isHTMLSpanElement(*element))
        elementIsSpanOrElementEquivalent = true;
    else {
        const Vector<OwnPtr<HTMLElementEquivalent> >& HTMLElementEquivalents = htmlElementEquivalents();
        size_t i;
        for (i = 0; i < HTMLElementEquivalents.size(); ++i) {
            if (HTMLElementEquivalents[i]->matches(element)) {
                elementIsSpanOrElementEquivalent = true;
                break;
            }
        }
    }

    if (!element->hasAttributes())
        return elementIsSpanOrElementEquivalent; // span, b, etc... without any attributes

    unsigned matchedAttributes = 0;
    const Vector<OwnPtr<HTMLAttributeEquivalent> >& HTMLAttributeEquivalents = htmlAttributeEquivalents();
    for (size_t i = 0; i < HTMLAttributeEquivalents.size(); ++i) {
        if (HTMLAttributeEquivalents[i]->matches(element) && HTMLAttributeEquivalents[i]->attributeName() != HTMLNames::dirAttr)
            matchedAttributes++;
    }

    if (!elementIsSpanOrElementEquivalent && !matchedAttributes)
        return false; // element is not a span, a html element equivalent, or font element.

    if (element->getAttribute(HTMLNames::classAttr) == AppleStyleSpanClass)
        matchedAttributes++;

    if (element->hasAttribute(HTMLNames::styleAttr)) {
        if (const StylePropertySet* style = element->inlineStyle()) {
            unsigned propertyCount = style->propertyCount();
            for (unsigned i = 0; i < propertyCount; ++i) {
                if (!isEditingProperty(style->propertyAt(i).id()))
                    return false;
            }
        }
        matchedAttributes++;
    }

    // font with color attribute, span with style attribute, etc...
    ASSERT(matchedAttributes <= element->attributeCount());
    return matchedAttributes >= element->attributeCount();
}

void EditingStyle::prepareToApplyAt(const Position& position, ShouldPreserveWritingDirection shouldPreserveWritingDirection)
{
    if (!m_mutableStyle)
        return;

    // ReplaceSelectionCommand::handleStyleSpans() requires that this function only removes the editing style.
    // If this function was modified in the future to delete all redundant properties, then add a boolean value to indicate
    // which one of editingStyleAtPosition or computedStyle is called.
    RefPtr<EditingStyle> editingStyleAtPosition = EditingStyle::create(position, EditingPropertiesInEffect);
    StylePropertySet* styleAtPosition = editingStyleAtPosition->m_mutableStyle.get();

    RefPtrWillBeRawPtr<CSSValue> unicodeBidi = nullptr;
    RefPtrWillBeRawPtr<CSSValue> direction = nullptr;
    if (shouldPreserveWritingDirection == PreserveWritingDirection) {
        unicodeBidi = m_mutableStyle->getPropertyCSSValue(CSSPropertyUnicodeBidi);
        direction = m_mutableStyle->getPropertyCSSValue(CSSPropertyDirection);
    }

    m_mutableStyle->removeEquivalentProperties(styleAtPosition);

    if (textAlignResolvingStartAndEnd(m_mutableStyle.get()) == textAlignResolvingStartAndEnd(styleAtPosition))
        m_mutableStyle->removeProperty(CSSPropertyTextAlign);

    if (getRGBAFontColor(m_mutableStyle.get()) == getRGBAFontColor(styleAtPosition))
        m_mutableStyle->removeProperty(CSSPropertyColor);

    if (hasTransparentBackgroundColor(m_mutableStyle.get())
        || cssValueToRGBA(m_mutableStyle->getPropertyCSSValue(CSSPropertyBackgroundColor).get()) == rgbaBackgroundColorInEffect(position.containerNode()))
        m_mutableStyle->removeProperty(CSSPropertyBackgroundColor);

    if (unicodeBidi && unicodeBidi->isPrimitiveValue()) {
        m_mutableStyle->setProperty(CSSPropertyUnicodeBidi, toCSSPrimitiveValue(unicodeBidi.get())->getValueID());
        if (direction && direction->isPrimitiveValue())
            m_mutableStyle->setProperty(CSSPropertyDirection, toCSSPrimitiveValue(direction.get())->getValueID());
    }
}

void EditingStyle::mergeTypingStyle(Document* document)
{
    ASSERT(document);

    RefPtr<EditingStyle> typingStyle = document->frame()->selection().typingStyle();
    if (!typingStyle || typingStyle == this)
        return;

    mergeStyle(typingStyle->style(), OverrideValues);
}

void EditingStyle::mergeInlineStyleOfElement(Element* element, CSSPropertyOverrideMode mode, PropertiesToInclude propertiesToInclude)
{
    ASSERT(element);
    if (!element->inlineStyle())
        return;

    switch (propertiesToInclude) {
    case AllProperties:
        mergeStyle(element->inlineStyle(), mode);
        return;
    case OnlyEditingInheritableProperties:
        mergeStyle(copyEditingProperties(element->inlineStyle(), OnlyInheritableEditingProperties).get(), mode);
        return;
    case EditingPropertiesInEffect:
        mergeStyle(copyEditingProperties(element->inlineStyle(), AllEditingProperties).get(), mode);
        return;
    }
}

static inline bool elementMatchesAndPropertyIsNotInInlineStyleDecl(const HTMLElementEquivalent* equivalent, const Element* element,
    EditingStyle::CSSPropertyOverrideMode mode, StylePropertySet* style)
{
    return equivalent->matches(element) && (!element->inlineStyle() || !equivalent->propertyExistsInStyle(element->inlineStyle()))
        && (mode == EditingStyle::OverrideValues || !equivalent->propertyExistsInStyle(style));
}

static PassRefPtrWillBeRawPtr<MutableStylePropertySet> extractEditingProperties(const StylePropertySet* style, EditingStyle::PropertiesToInclude propertiesToInclude)
{
    if (!style)
        return nullptr;

    switch (propertiesToInclude) {
    case EditingStyle::AllProperties:
    case EditingStyle::EditingPropertiesInEffect:
        return copyEditingProperties(style, AllEditingProperties);
    case EditingStyle::OnlyEditingInheritableProperties:
        return copyEditingProperties(style, OnlyInheritableEditingProperties);
    }

    ASSERT_NOT_REACHED();
    return nullptr;
}

void EditingStyle::mergeInlineAndImplicitStyleOfElement(Element* element, CSSPropertyOverrideMode mode, PropertiesToInclude propertiesToInclude)
{
    RefPtr<EditingStyle> styleFromRules = EditingStyle::create();
    styleFromRules->mergeStyleFromRulesForSerialization(element);
    styleFromRules->m_mutableStyle = extractEditingProperties(styleFromRules->m_mutableStyle.get(), propertiesToInclude);
    mergeStyle(styleFromRules->m_mutableStyle.get(), mode);

    mergeInlineStyleOfElement(element, mode, propertiesToInclude);

    const Vector<OwnPtr<HTMLElementEquivalent> >& elementEquivalents = htmlElementEquivalents();
    for (size_t i = 0; i < elementEquivalents.size(); ++i) {
        if (elementMatchesAndPropertyIsNotInInlineStyleDecl(elementEquivalents[i].get(), element, mode, m_mutableStyle.get()))
            elementEquivalents[i]->addToStyle(element, this);
    }

    const Vector<OwnPtr<HTMLAttributeEquivalent> >& attributeEquivalents = htmlAttributeEquivalents();
    for (size_t i = 0; i < attributeEquivalents.size(); ++i) {
        if (attributeEquivalents[i]->attributeName() == HTMLNames::dirAttr)
            continue; // We don't want to include directionality
        if (elementMatchesAndPropertyIsNotInInlineStyleDecl(attributeEquivalents[i].get(), element, mode, m_mutableStyle.get()))
            attributeEquivalents[i]->addToStyle(element, this);
    }
}

PassRefPtr<EditingStyle> EditingStyle::wrappingStyleForSerialization(Node* context, bool shouldAnnotate)
{
    RefPtr<EditingStyle> wrappingStyle;
    if (shouldAnnotate) {
        wrappingStyle = EditingStyle::create(context, EditingStyle::EditingPropertiesInEffect);

        // Styles that Mail blockquotes contribute should only be placed on the Mail blockquote,
        // to help us differentiate those styles from ones that the user has applied.
        // This helps us get the color of content pasted into blockquotes right.
        wrappingStyle->removeStyleAddedByNode(enclosingNodeOfType(firstPositionInOrBeforeNode(context), isMailBlockquote, CanCrossEditingBoundary));

        // Call collapseTextDecorationProperties first or otherwise it'll copy the value over from in-effect to text-decorations.
        wrappingStyle->collapseTextDecorationProperties();

        return wrappingStyle.release();
    }

    wrappingStyle = EditingStyle::create();

    // When not annotating for interchange, we only preserve inline style declarations.
    for (Node* node = context; node && !node->isDocumentNode(); node = node->parentNode()) {
        if (node->isStyledElement() && !isMailBlockquote(node)) {
            wrappingStyle->mergeInlineAndImplicitStyleOfElement(toElement(node), EditingStyle::DoNotOverrideValues,
                EditingStyle::EditingPropertiesInEffect);
        }
    }

    return wrappingStyle.release();
}


static void mergeTextDecorationValues(CSSValueList* mergedValue, const CSSValueList* valueToMerge)
{
    DEFINE_STATIC_REF(CSSPrimitiveValue, underline, (CSSPrimitiveValue::createIdentifier(CSSValueUnderline)));
    DEFINE_STATIC_REF(CSSPrimitiveValue, lineThrough, (CSSPrimitiveValue::createIdentifier(CSSValueLineThrough)));

    if (valueToMerge->hasValue(underline) && !mergedValue->hasValue(underline))
        mergedValue->append(underline);

    if (valueToMerge->hasValue(lineThrough) && !mergedValue->hasValue(lineThrough))
        mergedValue->append(lineThrough);
}

void EditingStyle::mergeStyle(const StylePropertySet* style, CSSPropertyOverrideMode mode)
{
    if (!style)
        return;

    if (!m_mutableStyle) {
        m_mutableStyle = style->mutableCopy();
        return;
    }

    unsigned propertyCount = style->propertyCount();
    for (unsigned i = 0; i < propertyCount; ++i) {
        StylePropertySet::PropertyReference property = style->propertyAt(i);
        RefPtrWillBeRawPtr<CSSValue> value = m_mutableStyle->getPropertyCSSValue(property.id());

        // text decorations never override values
        if ((property.id() == textDecorationPropertyForEditing() || property.id() == CSSPropertyWebkitTextDecorationsInEffect) && property.value()->isValueList() && value) {
            if (value->isValueList()) {
                mergeTextDecorationValues(toCSSValueList(value.get()), toCSSValueList(property.value()));
                continue;
            }
            value = nullptr; // text-decoration: none is equivalent to not having the property
        }

        if (mode == OverrideValues || (mode == DoNotOverrideValues && !value))
            m_mutableStyle->setProperty(property.id(), property.value()->cssText(), property.isImportant());
    }
}

static PassRefPtrWillBeRawPtr<MutableStylePropertySet> styleFromMatchedRulesForElement(Element* element, unsigned rulesToInclude)
{
    RefPtrWillBeRawPtr<MutableStylePropertySet> style = MutableStylePropertySet::create();
    RefPtrWillBeRawPtr<StyleRuleList> matchedRules = element->document().ensureStyleResolver().styleRulesForElement(element, rulesToInclude);
    if (matchedRules) {
        for (unsigned i = 0; i < matchedRules->m_list.size(); ++i)
            style->mergeAndOverrideOnConflict(&matchedRules->m_list[i]->properties());
    }
    return style.release();
}

void EditingStyle::mergeStyleFromRules(Element* element)
{
    RefPtrWillBeRawPtr<MutableStylePropertySet> styleFromMatchedRules = styleFromMatchedRulesForElement(element,
        StyleResolver::AuthorCSSRules | StyleResolver::CrossOriginCSSRules);
    // Styles from the inline style declaration, held in the variable "style", take precedence
    // over those from matched rules.
    if (m_mutableStyle)
        styleFromMatchedRules->mergeAndOverrideOnConflict(m_mutableStyle.get());

    clear();
    m_mutableStyle = styleFromMatchedRules;
}

void EditingStyle::mergeStyleFromRulesForSerialization(Element* element)
{
    mergeStyleFromRules(element);

    // The property value, if it's a percentage, may not reflect the actual computed value.
    // For example: style="height: 1%; overflow: visible;" in quirksmode
    // FIXME: There are others like this, see <rdar://problem/5195123> Slashdot copy/paste fidelity problem
    RefPtr<CSSComputedStyleDeclaration> computedStyleForElement = CSSComputedStyleDeclaration::create(element);
    RefPtrWillBeRawPtr<MutableStylePropertySet> fromComputedStyle = MutableStylePropertySet::create();
    {
        unsigned propertyCount = m_mutableStyle->propertyCount();
        for (unsigned i = 0; i < propertyCount; ++i) {
            StylePropertySet::PropertyReference property = m_mutableStyle->propertyAt(i);
            CSSValue* value = property.value();
            if (!value->isPrimitiveValue())
                continue;
            if (toCSSPrimitiveValue(value)->isPercentage()) {
                if (RefPtrWillBeRawPtr<CSSValue> computedPropertyValue = computedStyleForElement->getPropertyCSSValue(property.id()))
                    fromComputedStyle->addParsedProperty(CSSProperty(property.id(), computedPropertyValue));
            }
        }
    }
    m_mutableStyle->mergeAndOverrideOnConflict(fromComputedStyle.get());
}

static void removePropertiesInStyle(MutableStylePropertySet* styleToRemovePropertiesFrom, StylePropertySet* style)
{
    unsigned propertyCount = style->propertyCount();
    Vector<CSSPropertyID> propertiesToRemove(propertyCount);
    for (unsigned i = 0; i < propertyCount; ++i)
        propertiesToRemove[i] = style->propertyAt(i).id();

    styleToRemovePropertiesFrom->removePropertiesInSet(propertiesToRemove.data(), propertiesToRemove.size());
}

void EditingStyle::removeStyleFromRulesAndContext(Element* element, Node* context)
{
    ASSERT(element);
    if (!m_mutableStyle)
        return;

    // 1. Remove style from matched rules because style remain without repeating it in inline style declaration
    RefPtrWillBeRawPtr<MutableStylePropertySet> styleFromMatchedRules = styleFromMatchedRulesForElement(element, StyleResolver::AllButEmptyCSSRules);
    if (styleFromMatchedRules && !styleFromMatchedRules->isEmpty())
        m_mutableStyle = getPropertiesNotIn(m_mutableStyle.get(), styleFromMatchedRules->ensureCSSStyleDeclaration());

    // 2. Remove style present in context and not overriden by matched rules.
    RefPtr<EditingStyle> computedStyle = EditingStyle::create(context, EditingPropertiesInEffect);
    if (computedStyle->m_mutableStyle) {
        if (!computedStyle->m_mutableStyle->getPropertyCSSValue(CSSPropertyBackgroundColor))
            computedStyle->m_mutableStyle->setProperty(CSSPropertyBackgroundColor, CSSValueTransparent);

        removePropertiesInStyle(computedStyle->m_mutableStyle.get(), styleFromMatchedRules.get());
        m_mutableStyle = getPropertiesNotIn(m_mutableStyle.get(), computedStyle->m_mutableStyle->ensureCSSStyleDeclaration());
    }

    // 3. If this element is a span and has display: inline or float: none, remove them unless they are overriden by rules.
    // These rules are added by serialization code to wrap text nodes.
    if (isStyleSpanOrSpanWithOnlyStyleAttribute(element)) {
        if (!styleFromMatchedRules->getPropertyCSSValue(CSSPropertyDisplay) && getIdentifierValue(m_mutableStyle.get(), CSSPropertyDisplay) == CSSValueInline)
            m_mutableStyle->removeProperty(CSSPropertyDisplay);
        if (!styleFromMatchedRules->getPropertyCSSValue(CSSPropertyFloat) && getIdentifierValue(m_mutableStyle.get(), CSSPropertyFloat) == CSSValueNone)
            m_mutableStyle->removeProperty(CSSPropertyFloat);
    }
}

void EditingStyle::removePropertiesInElementDefaultStyle(Element* element)
{
    if (!m_mutableStyle || m_mutableStyle->isEmpty())
        return;

    RefPtr<StylePropertySet> defaultStyle = styleFromMatchedRulesForElement(element, StyleResolver::UAAndUserCSSRules);

    removePropertiesInStyle(m_mutableStyle.get(), defaultStyle.get());
}

void EditingStyle::forceInline()
{
    if (!m_mutableStyle)
        m_mutableStyle = MutableStylePropertySet::create();
    const bool propertyIsImportant = true;
    m_mutableStyle->setProperty(CSSPropertyDisplay, CSSValueInline, propertyIsImportant);
}

int EditingStyle::legacyFontSize(Document* document) const
{
    RefPtrWillBeRawPtr<CSSValue> cssValue = m_mutableStyle->getPropertyCSSValue(CSSPropertyFontSize);
    if (!cssValue || !cssValue->isPrimitiveValue())
        return 0;
    return legacyFontSizeFromCSSValue(document, toCSSPrimitiveValue(cssValue.get()),
        m_shouldUseFixedDefaultFontSize, AlwaysUseLegacyFontSize);
}

PassRefPtr<EditingStyle> EditingStyle::styleAtSelectionStart(const VisibleSelection& selection, bool shouldUseBackgroundColorInEffect)
{
    if (selection.isNone())
        return nullptr;

    Position position = adjustedSelectionStartForStyleComputation(selection);

    // If the pos is at the end of a text node, then this node is not fully selected.
    // Move it to the next deep equivalent position to avoid removing the style from this node.
    // e.g. if pos was at Position("hello", 5) in <b>hello<div>world</div></b>, we want Position("world", 0) instead.
    // We only do this for range because caret at Position("hello", 5) in <b>hello</b>world should give you font-weight: bold.
    Node* positionNode = position.containerNode();
    if (selection.isRange() && positionNode && positionNode->isTextNode() && position.computeOffsetInContainerNode() == positionNode->maxCharacterOffset())
        position = nextVisuallyDistinctCandidate(position);

    Element* element = position.element();
    if (!element)
        return nullptr;

    RefPtr<EditingStyle> style = EditingStyle::create(element, EditingStyle::AllProperties);
    style->mergeTypingStyle(&element->document());

    // If background color is transparent, traverse parent nodes until we hit a different value or document root
    // Also, if the selection is a range, ignore the background color at the start of selection,
    // and find the background color of the common ancestor.
    if (shouldUseBackgroundColorInEffect && (selection.isRange() || hasTransparentBackgroundColor(style->m_mutableStyle.get()))) {
        RefPtrWillBeRawPtr<Range> range(selection.toNormalizedRange());
        if (PassRefPtrWillBeRawPtr<CSSValue> value = backgroundColorInEffect(range->commonAncestorContainer(IGNORE_EXCEPTION)))
            style->setProperty(CSSPropertyBackgroundColor, value->cssText());
    }

    return style;
}

WritingDirection EditingStyle::textDirectionForSelection(const VisibleSelection& selection, EditingStyle* typingStyle, bool& hasNestedOrMultipleEmbeddings)
{
    hasNestedOrMultipleEmbeddings = true;

    if (selection.isNone())
        return NaturalWritingDirection;

    Position position = selection.start().downstream();

    Node* node = position.deprecatedNode();
    if (!node)
        return NaturalWritingDirection;

    Position end;
    if (selection.isRange()) {
        end = selection.end().upstream();

        ASSERT(end.document());
        Node* pastLast = Range::create(*end.document(), position.parentAnchoredEquivalent(), end.parentAnchoredEquivalent())->pastLastNode();
        for (Node* n = node; n && n != pastLast; n = NodeTraversal::next(*n)) {
            if (!n->isStyledElement())
                continue;

            RefPtr<CSSComputedStyleDeclaration> style = CSSComputedStyleDeclaration::create(n);
            RefPtrWillBeRawPtr<CSSValue> unicodeBidi = style->getPropertyCSSValue(CSSPropertyUnicodeBidi);
            if (!unicodeBidi || !unicodeBidi->isPrimitiveValue())
                continue;

            CSSValueID unicodeBidiValue = toCSSPrimitiveValue(unicodeBidi.get())->getValueID();
            if (unicodeBidiValue == CSSValueEmbed || unicodeBidiValue == CSSValueBidiOverride)
                return NaturalWritingDirection;
        }
    }

    if (selection.isCaret()) {
        WritingDirection direction;
        if (typingStyle && typingStyle->textDirection(direction)) {
            hasNestedOrMultipleEmbeddings = false;
            return direction;
        }
        node = selection.visibleStart().deepEquivalent().deprecatedNode();
    }

    // The selection is either a caret with no typing attributes or a range in which no embedding is added, so just use the start position
    // to decide.
    Node* block = enclosingBlock(node);
    WritingDirection foundDirection = NaturalWritingDirection;

    for (; node != block; node = node->parentNode()) {
        if (!node->isStyledElement())
            continue;

        RefPtr<CSSComputedStyleDeclaration> style = CSSComputedStyleDeclaration::create(node);
        RefPtrWillBeRawPtr<CSSValue> unicodeBidi = style->getPropertyCSSValue(CSSPropertyUnicodeBidi);
        if (!unicodeBidi || !unicodeBidi->isPrimitiveValue())
            continue;

        CSSValueID unicodeBidiValue = toCSSPrimitiveValue(unicodeBidi.get())->getValueID();
        if (unicodeBidiValue == CSSValueNormal)
            continue;

        if (unicodeBidiValue == CSSValueBidiOverride)
            return NaturalWritingDirection;

        ASSERT(unicodeBidiValue == CSSValueEmbed);
        RefPtrWillBeRawPtr<CSSValue> direction = style->getPropertyCSSValue(CSSPropertyDirection);
        if (!direction || !direction->isPrimitiveValue())
            continue;

        int directionValue = toCSSPrimitiveValue(direction.get())->getValueID();
        if (directionValue != CSSValueLtr && directionValue != CSSValueRtl)
            continue;

        if (foundDirection != NaturalWritingDirection)
            return NaturalWritingDirection;

        // In the range case, make sure that the embedding element persists until the end of the range.
        if (selection.isRange() && !end.deprecatedNode()->isDescendantOf(node))
            return NaturalWritingDirection;

        foundDirection = directionValue == CSSValueLtr ? LeftToRightWritingDirection : RightToLeftWritingDirection;
    }
    hasNestedOrMultipleEmbeddings = false;
    return foundDirection;
}

static void reconcileTextDecorationProperties(MutableStylePropertySet* style)
{
    RefPtrWillBeRawPtr<CSSValue> textDecorationsInEffect = style->getPropertyCSSValue(CSSPropertyWebkitTextDecorationsInEffect);
    RefPtrWillBeRawPtr<CSSValue> textDecoration = style->getPropertyCSSValue(textDecorationPropertyForEditing());
    // We shouldn't have both text-decoration and -webkit-text-decorations-in-effect because that wouldn't make sense.
    ASSERT(!textDecorationsInEffect || !textDecoration);
    if (textDecorationsInEffect) {
        style->setProperty(textDecorationPropertyForEditing(), textDecorationsInEffect->cssText());
        style->removeProperty(CSSPropertyWebkitTextDecorationsInEffect);
        textDecoration = textDecorationsInEffect;
    }

    // If text-decoration is set to "none", remove the property because we don't want to add redundant "text-decoration: none".
    if (textDecoration && !textDecoration->isValueList())
        style->removeProperty(textDecorationPropertyForEditing());
}

StyleChange::StyleChange(EditingStyle* style, const Position& position)
    : m_applyBold(false)
    , m_applyItalic(false)
    , m_applyUnderline(false)
    , m_applyLineThrough(false)
    , m_applySubscript(false)
    , m_applySuperscript(false)
{
    Document* document = position.document();
    if (!style || !style->style() || !document || !document->frame())
        return;

    RefPtr<CSSComputedStyleDeclaration> computedStyle = position.computedStyle();
    // FIXME: take care of background-color in effect
    RefPtrWillBeRawPtr<MutableStylePropertySet> mutableStyle = getPropertiesNotIn(style->style(), computedStyle.get());

    reconcileTextDecorationProperties(mutableStyle.get());
    if (!document->frame()->editor().shouldStyleWithCSS())
        extractTextStyles(document, mutableStyle.get(), computedStyle->useFixedFontDefaultSize());

    // Changing the whitespace style in a tab span would collapse the tab into a space.
    if (isTabSpanTextNode(position.deprecatedNode()) || isTabSpanNode((position.deprecatedNode())))
        mutableStyle->removeProperty(CSSPropertyWhiteSpace);

    // If unicode-bidi is present in mutableStyle and direction is not, then add direction to mutableStyle.
    // FIXME: Shouldn't this be done in getPropertiesNotIn?
    if (mutableStyle->getPropertyCSSValue(CSSPropertyUnicodeBidi) && !style->style()->getPropertyCSSValue(CSSPropertyDirection))
        mutableStyle->setProperty(CSSPropertyDirection, style->style()->getPropertyValue(CSSPropertyDirection));

    // Save the result for later
    m_cssStyle = mutableStyle->asText().stripWhiteSpace();
}

static void setTextDecorationProperty(MutableStylePropertySet* style, const CSSValueList* newTextDecoration, CSSPropertyID propertyID)
{
    if (newTextDecoration->length())
        style->setProperty(propertyID, newTextDecoration->cssText(), style->propertyIsImportant(propertyID));
    else {
        // text-decoration: none is redundant since it does not remove any text decorations.
        style->removeProperty(propertyID);
    }
}

void StyleChange::extractTextStyles(Document* document, MutableStylePropertySet* style, bool shouldUseFixedFontDefaultSize)
{
    ASSERT(style);

    if (getIdentifierValue(style, CSSPropertyFontWeight) == CSSValueBold) {
        style->removeProperty(CSSPropertyFontWeight);
        m_applyBold = true;
    }

    int fontStyle = getIdentifierValue(style, CSSPropertyFontStyle);
    if (fontStyle == CSSValueItalic || fontStyle == CSSValueOblique) {
        style->removeProperty(CSSPropertyFontStyle);
        m_applyItalic = true;
    }

    // Assuming reconcileTextDecorationProperties has been called, there should not be -webkit-text-decorations-in-effect
    // Furthermore, text-decoration: none has been trimmed so that text-decoration property is always a CSSValueList.
    RefPtrWillBeRawPtr<CSSValue> textDecoration = style->getPropertyCSSValue(textDecorationPropertyForEditing());
    if (textDecoration && textDecoration->isValueList()) {
        DEFINE_STATIC_REF(CSSPrimitiveValue, underline, (CSSPrimitiveValue::createIdentifier(CSSValueUnderline)));
        DEFINE_STATIC_REF(CSSPrimitiveValue, lineThrough, (CSSPrimitiveValue::createIdentifier(CSSValueLineThrough)));

        RefPtrWillBeRawPtr<CSSValueList> newTextDecoration = toCSSValueList(textDecoration.get())->copy();
        if (newTextDecoration->removeAll(underline))
            m_applyUnderline = true;
        if (newTextDecoration->removeAll(lineThrough))
            m_applyLineThrough = true;

        // If trimTextDecorations, delete underline and line-through
        setTextDecorationProperty(style, newTextDecoration.get(), textDecorationPropertyForEditing());
    }

    int verticalAlign = getIdentifierValue(style, CSSPropertyVerticalAlign);
    switch (verticalAlign) {
    case CSSValueSub:
        style->removeProperty(CSSPropertyVerticalAlign);
        m_applySubscript = true;
        break;
    case CSSValueSuper:
        style->removeProperty(CSSPropertyVerticalAlign);
        m_applySuperscript = true;
        break;
    }

    if (style->getPropertyCSSValue(CSSPropertyColor)) {
        m_applyFontColor = Color(getRGBAFontColor(style)).serialized();
        style->removeProperty(CSSPropertyColor);
    }

    m_applyFontFace = style->getPropertyValue(CSSPropertyFontFamily);
    // Remove single quotes for Outlook 2007 compatibility. See https://bugs.webkit.org/show_bug.cgi?id=79448
    m_applyFontFace.replaceWithLiteral('\'', "");
    style->removeProperty(CSSPropertyFontFamily);

    if (RefPtrWillBeRawPtr<CSSValue> fontSize = style->getPropertyCSSValue(CSSPropertyFontSize)) {
        if (!fontSize->isPrimitiveValue())
            style->removeProperty(CSSPropertyFontSize); // Can't make sense of the number. Put no font size.
        else if (int legacyFontSize = legacyFontSizeFromCSSValue(document, toCSSPrimitiveValue(fontSize.get()),
                shouldUseFixedFontDefaultSize, UseLegacyFontSizeOnlyIfPixelValuesMatch)) {
            m_applyFontSize = String::number(legacyFontSize);
            style->removeProperty(CSSPropertyFontSize);
        }
    }
}

static void diffTextDecorations(MutableStylePropertySet* style, CSSPropertyID propertID, CSSValue* refTextDecoration)
{
    RefPtrWillBeRawPtr<CSSValue> textDecoration = style->getPropertyCSSValue(propertID);
    if (!textDecoration || !textDecoration->isValueList() || !refTextDecoration || !refTextDecoration->isValueList())
        return;

    RefPtrWillBeRawPtr<CSSValueList> newTextDecoration = toCSSValueList(textDecoration.get())->copy();
    CSSValueList* valuesInRefTextDecoration = toCSSValueList(refTextDecoration);

    for (size_t i = 0; i < valuesInRefTextDecoration->length(); i++)
        newTextDecoration->removeAll(valuesInRefTextDecoration->item(i));

    setTextDecorationProperty(style, newTextDecoration.get(), propertID);
}

static bool fontWeightIsBold(CSSValue* fontWeight)
{
    if (!fontWeight->isPrimitiveValue())
        return false;

    // Because b tag can only bold text, there are only two states in plain html: bold and not bold.
    // Collapse all other values to either one of these two states for editing purposes.
    switch (toCSSPrimitiveValue(fontWeight)->getValueID()) {
        case CSSValue100:
        case CSSValue200:
        case CSSValue300:
        case CSSValue400:
        case CSSValue500:
        case CSSValueNormal:
            return false;
        case CSSValueBold:
        case CSSValue600:
        case CSSValue700:
        case CSSValue800:
        case CSSValue900:
            return true;
        default:
            break;
    }

    ASSERT_NOT_REACHED(); // For CSSValueBolder and CSSValueLighter
    return false;
}

static bool fontWeightNeedsResolving(CSSValue* fontWeight)
{
    if (!fontWeight->isPrimitiveValue())
        return true;

    CSSValueID value = toCSSPrimitiveValue(fontWeight)->getValueID();
    return value == CSSValueLighter || value == CSSValueBolder;
}

PassRefPtrWillBeRawPtr<MutableStylePropertySet> getPropertiesNotIn(StylePropertySet* styleWithRedundantProperties, CSSStyleDeclaration* baseStyle)
{
    ASSERT(styleWithRedundantProperties);
    ASSERT(baseStyle);
    RefPtrWillBeRawPtr<MutableStylePropertySet> result = styleWithRedundantProperties->mutableCopy();

    result->removeEquivalentProperties(baseStyle);

    RefPtrWillBeRawPtr<CSSValue> baseTextDecorationsInEffect = baseStyle->getPropertyCSSValueInternal(CSSPropertyWebkitTextDecorationsInEffect);
    diffTextDecorations(result.get(), textDecorationPropertyForEditing(), baseTextDecorationsInEffect.get());
    diffTextDecorations(result.get(), CSSPropertyWebkitTextDecorationsInEffect, baseTextDecorationsInEffect.get());

    if (RefPtrWillBeRawPtr<CSSValue> baseFontWeight = baseStyle->getPropertyCSSValueInternal(CSSPropertyFontWeight)) {
        if (RefPtrWillBeRawPtr<CSSValue> fontWeight = result->getPropertyCSSValue(CSSPropertyFontWeight)) {
            if (!fontWeightNeedsResolving(fontWeight.get()) && (fontWeightIsBold(fontWeight.get()) == fontWeightIsBold(baseFontWeight.get())))
                result->removeProperty(CSSPropertyFontWeight);
        }
    }

    if (baseStyle->getPropertyCSSValueInternal(CSSPropertyColor) && getRGBAFontColor(result.get()) == getRGBAFontColor(baseStyle))
        result->removeProperty(CSSPropertyColor);

    if (baseStyle->getPropertyCSSValueInternal(CSSPropertyTextAlign)
        && textAlignResolvingStartAndEnd(result.get()) == textAlignResolvingStartAndEnd(baseStyle))
        result->removeProperty(CSSPropertyTextAlign);

    if (baseStyle->getPropertyCSSValueInternal(CSSPropertyBackgroundColor) && getRGBABackgroundColor(result.get()) == getRGBABackgroundColor(baseStyle))
        result->removeProperty(CSSPropertyBackgroundColor);

    return result.release();
}

CSSValueID getIdentifierValue(StylePropertySet* style, CSSPropertyID propertyID)
{
    if (!style)
        return CSSValueInvalid;
    RefPtrWillBeRawPtr<CSSValue> value = style->getPropertyCSSValue(propertyID);
    if (!value || !value->isPrimitiveValue())
        return CSSValueInvalid;
    return toCSSPrimitiveValue(value.get())->getValueID();
}

CSSValueID getIdentifierValue(CSSStyleDeclaration* style, CSSPropertyID propertyID)
{
    if (!style)
        return CSSValueInvalid;
    RefPtrWillBeRawPtr<CSSValue> value = style->getPropertyCSSValueInternal(propertyID);
    if (!value || !value->isPrimitiveValue())
        return CSSValueInvalid;
    return toCSSPrimitiveValue(value.get())->getValueID();
}

static bool isCSSValueLength(CSSPrimitiveValue* value)
{
    return value->isFontIndependentLength();
}

int legacyFontSizeFromCSSValue(Document* document, CSSPrimitiveValue* value, bool shouldUseFixedFontDefaultSize, LegacyFontSizeMode mode)
{
    if (isCSSValueLength(value)) {
        int pixelFontSize = value->getIntValue(CSSPrimitiveValue::CSS_PX);
        int legacyFontSize = FontSize::legacyFontSize(document, pixelFontSize, shouldUseFixedFontDefaultSize);
        // Use legacy font size only if pixel value matches exactly to that of legacy font size.
        int cssPrimitiveEquivalent = legacyFontSize - 1 + CSSValueXSmall;
        if (mode == AlwaysUseLegacyFontSize || FontSize::fontSizeForKeyword(document, cssPrimitiveEquivalent, shouldUseFixedFontDefaultSize) == pixelFontSize)
            return legacyFontSize;

        return 0;
    }

    if (CSSValueXSmall <= value->getValueID() && value->getValueID() <= CSSValueWebkitXxxLarge)
        return value->getValueID() - CSSValueXSmall + 1;

    return 0;
}

bool isTransparentColorValue(CSSValue* cssValue)
{
    if (!cssValue)
        return true;
    if (!cssValue->isPrimitiveValue())
        return false;
    CSSPrimitiveValue* value = toCSSPrimitiveValue(cssValue);
    if (value->isRGBColor())
        return !alphaChannel(value->getRGBA32Value());
    return value->getValueID() == CSSValueTransparent;
}

bool hasTransparentBackgroundColor(CSSStyleDeclaration* style)
{
    RefPtrWillBeRawPtr<CSSValue> cssValue = style->getPropertyCSSValueInternal(CSSPropertyBackgroundColor);
    return isTransparentColorValue(cssValue.get());
}

bool hasTransparentBackgroundColor(StylePropertySet* style)
{
    RefPtrWillBeRawPtr<CSSValue> cssValue = style->getPropertyCSSValue(CSSPropertyBackgroundColor);
    return isTransparentColorValue(cssValue.get());
}

PassRefPtrWillBeRawPtr<CSSValue> backgroundColorInEffect(Node* node)
{
    for (Node* ancestor = node; ancestor; ancestor = ancestor->parentNode()) {
        RefPtr<CSSComputedStyleDeclaration> ancestorStyle = CSSComputedStyleDeclaration::create(ancestor);
        if (!hasTransparentBackgroundColor(ancestorStyle.get()))
            return ancestorStyle->getPropertyCSSValue(CSSPropertyBackgroundColor);
    }
    return nullptr;
}

}
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root/Source/core/editing/EditingStyle.cpp

DEFINITIONS
