Add support for multiple text decorations with same line positioning

Source/core/style/AppliedTextDecoration.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef AppliedTextDecoration_h
 #define AppliedTextDecoration_h
 
 #include "core/css/StyleColor.h"
 #include "core/style/ComputedStyleConstants.h"
 #include "wtf/Allocator.h"
 
 namespace blink {
 
 class AppliedTextDecoration {
     ALLOW_ONLY_INLINE_ALLOCATION();
 public:
-    AppliedTextDecoration(TextDecoration, TextDecorationStyle, StyleColor);
+    AppliedTextDecoration(TextDecoration, TextDecorationStyle, Color, bool isAffectedByPropagatedColors = false);
     explicit AppliedTextDecoration(TextDecoration);
 
-    TextDecoration line() const { return static_cast<TextDecoration>(m_line); }
+    TextDecoration lines() const { return static_cast<TextDecoration>(m_lines); }
     TextDecorationStyle style() const { return static_cast<TextDecorationStyle>(m_style); }
+    Color color() const { return m_color; }
+    bool isAffectedByPropagatedColors() const { return m_isAffectedByPropagatedColors; }
 
-    bool isSimpleUnderline() const { return m_line == TextDecorationUnderline && m_style == TextDecorationStyleSolid && m_color.isCurrentColor(); }
+    void applyPropagatedColor(Color color)
+    {
+        ASSERT(m_isAffectedByPropagatedColors);
+        m_color = color;
+    }
+
     bool operator==(const AppliedTextDecoration&) const;
     bool operator!=(const AppliedTextDecoration& o) const { return !(*this == o); }
 
 private:
-    unsigned m_line : TextDecorationBits;
+    unsigned m_lines : TextDecorationBits;
     unsigned m_style : 3; // TextDecorationStyle
-    StyleColor m_color;
+    unsigned m_isAffectedByPropagatedColors : 1;
+    Color m_color;
 };
 
 } // namespace blink
 
 #endif // AppliedTextDecoration_h