Add support for multiple text decorations with same line positioning

Source/core/style/ComputedStyle.h

Index: Source/core/style/ComputedStyle.h
diff --git a/Source/core/style/ComputedStyle.h b/Source/core/style/ComputedStyle.h
index 4a0263de57fdd7cc4e9a6cf0bd323239f1ec58ae..7a8afb21bd75499295f9defd5487d790b4d9efdb 100644
--- a/Source/core/style/ComputedStyle.h
+++ b/Source/core/style/ComputedStyle.h
@@ -171,7 +171,7 @@ protected:
                 && (_visibility == other._visibility)
                 && (_text_align == other._text_align)
                 && (_text_transform == other._text_transform)
-                && (m_textUnderline == other.m_textUnderline)
+                && (m_hasSimpleUnderline == other.m_hasSimpleUnderline)
                 && (_cursor_style == other._cursor_style)
                 && (_direction == other._direction)
                 && (_white_space == other._white_space)
@@ -193,7 +193,7 @@ protected:
         unsigned _visibility : 2; // EVisibility
         unsigned _text_align : 4; // ETextAlign
         unsigned _text_transform : 2; // ETextTransform
-        unsigned m_textUnderline : 1;
+        unsigned m_hasSimpleUnderline : 1; // True if 'underline solid currentColor' is the only text decoration on this element
         unsigned _cursor_style : 6; // ECursor
         unsigned _direction : 1; // TextDirection
         unsigned _white_space : 3; // EWhiteSpace
@@ -297,7 +297,7 @@ protected:
         inherited_flags._visibility = initialVisibility();
         inherited_flags._text_align = initialTextAlign();
         inherited_flags._text_transform = initialTextTransform();
-        inherited_flags.m_textUnderline = false;
+        inherited_flags.m_hasSimpleUnderline = false;
         inherited_flags._cursor_style = initialCursor();
         inherited_flags._direction = initialDirection();
         inherited_flags._white_space = initialWhiteSpace();
@@ -587,7 +587,7 @@ public:
     TextDecoration textDecorationsInEffect() const;
     const Vector<AppliedTextDecoration>& appliedTextDecorations() const;
     TextDecoration textDecoration() const { return static_cast<TextDecoration>(visual->textDecoration); }
-    TextUnderlinePosition textUnderlinePosition() const { return static_cast<TextUnderlinePosition>(rareInheritedData->m_textUnderlinePosition); }
+    TextUnderlinePosition textUnderlinePosition() const { return static_cast<TextUnderlinePosition>(rareInheritedData->m_hasSimpleUnderlinePosition); }
     TextDecorationStyle textDecorationStyle() const { return static_cast<TextDecorationStyle>(rareNonInheritedData->m_textDecorationStyle); }
     float wordSpacing() const;
     float letterSpacing() const;
@@ -1136,10 +1136,10 @@ public:
     void setTextAlignLast(TextAlignLast v) { SET_VAR(rareInheritedData, m_textAlignLast, v); }
     void setTextJustify(TextJustify v) { SET_VAR(rareInheritedData, m_textJustify, v); }
     void setTextTransform(ETextTransform v) { inherited_flags._text_transform = v; }
-    void applyTextDecorations();
+    void applyTextDecorations(bool overrideExistingColors);
     void clearAppliedTextDecorations();
     void setTextDecoration(TextDecoration v) { SET_VAR(visual, textDecoration, v); }
-    void setTextUnderlinePosition(TextUnderlinePosition v) { SET_VAR(rareInheritedData, m_textUnderlinePosition, v); }
+    void setTextUnderlinePosition(TextUnderlinePosition v) { SET_VAR(rareInheritedData, m_hasSimpleUnderlinePosition, v); }
     void setTextDecorationStyle(TextDecorationStyle v) { SET_VAR(rareNonInheritedData, m_textDecorationStyle, v); }
     void setDirection(TextDirection v) { inherited_flags._direction = v; }
     void setSelfOrAncestorHasDirAutoAttribute(bool v) { SET_VAR(rareInheritedData, m_selfOrAncestorHasDirAutoAttribute, v); }
@@ -1381,6 +1381,9 @@ public:
     void setSpeak(ESpeak s) { SET_VAR(rareInheritedData, speak, s); }
     void setTextCombine(TextCombine v) { SET_VAR(rareInheritedData, m_textCombine, v); }
     void setTextDecorationColor(const StyleColor& c) { SET_VAR(rareNonInheritedData, m_textDecorationColor, c); }
+
+    void setSimpleUnderlineColor(const Color& c) { SET_VAR(rareInheritedData, simpleUnderlineColor, c); }
+    void setSimpleUnderlineVisitedColor(const Color& c) { SET_VAR(rareInheritedData, simpleUnderlineVisitedColor, c); }
     void setTextEmphasisColor(const StyleColor& c) { SET_VAR_WITH_SETTER(rareInheritedData, textEmphasisColor, setTextEmphasisColor, c); }
     void setTextEmphasisFill(TextEmphasisFill fill) { SET_VAR(rareInheritedData, textEmphasisFill, fill); }
     void setTextEmphasisMark(TextEmphasisMark mark) { SET_VAR(rareInheritedData, textEmphasisMark, mark); }
@@ -1388,6 +1391,8 @@ public:
     void setTextEmphasisPosition(TextEmphasisPosition position) { SET_VAR(rareInheritedData, textEmphasisPosition, position); }
     bool setTextOrientation(TextOrientation);
 
+    Color visitedDependentSimpleUnderlineColor() const { return (insideLink() == InsideVisitedLink) ? rareInheritedData->simpleUnderlineVisitedColor : rareInheritedData->simpleUnderlineColor; }
+
     void setMotionPath(PassRefPtr<StyleMotionPath>);
     void resetMotionPath();
     void setMotionOffset(const Length& motionOffset) { SET_VAR(rareNonInheritedData.access()->m_transform, m_motion.m_offset, motionOffset); }
@@ -1860,6 +1865,7 @@ private:
 
     void appendContent(PassOwnPtrWillBeRawPtr<ContentData>);
     void addAppliedTextDecoration(const AppliedTextDecoration&);
+    void updateAppliedTextDecoration(size_t index, Color newColor);
     void applyMotionPathTransform(float originX, float originY, TransformationMatrix&) const;
 
     bool diffNeedsFullLayoutAndPaintInvalidation(const ComputedStyle& other) const;