Avoid unnecessary CoW for outer DataRef when applying transform-origin

third_party/WebKit/Source/core/style/ComputedStyle.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * 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
@@ skipping 72 matching lines @@
 #include "wtf/RefCounted.h"
 #include "wtf/StdLibExtras.h"
 #include "wtf/Vector.h"
 
 template<typename T, typename U> inline bool compareEqual(const T& t, const U& u) { return t == static_cast<T>(u); }
 
 #define SET_VAR(group, variable, value) \
     if (!compareEqual(group->variable, value)) \
         group.access()->variable = value
 
+#define SET_NESTED_VAR(group, base, variable, value)            \
+    if (!compareEqual(group->base->variable, value))            \
+        group.access()->base.access()->variable = value
+
 #define SET_VAR_WITH_SETTER(group, getter, setter, value)    \
     if (!compareEqual(group->getter(), value)) \
         group.access()->setter(value)
 
 #define SET_BORDERVALUE_COLOR(group, variable, value) \
     if (!compareEqual(group->variable.color(), value)) \
         group.access()->variable.setColor(value)
 
 namespace blink {
 
@@ skipping 1294 matching lines @@
     // For valid values of column-break-inside see http://www.w3.org/TR/css3-multicol/#break-before-break-after-break-inside
     void setColumnBreakInside(EPageBreak p) { ASSERT(p == PBAUTO || p == PBAVOID); SET_VAR(rareNonInheritedData.access()->m_multiCol, m_breakInside, p); }
     void setColumnBreakAfter(EPageBreak p) { SET_VAR(rareNonInheritedData.access()->m_multiCol, m_breakAfter, p); }
     void inheritColumnPropertiesFrom(const ComputedStyle& parent) { rareNonInheritedData.access()->m_multiCol = parent.rareNonInheritedData->m_multiCol; }
     void setHasInlineTransform(bool b) { SET_VAR(rareNonInheritedData, m_hasInlineTransform, b); }
     void setHasCompositorProxy(bool b) { SET_VAR(rareNonInheritedData, m_hasCompositorProxy, b); }
     void setTransform(const TransformOperations& ops) { SET_VAR(rareNonInheritedData.access()->m_transform, m_operations, ops); }
     void setTransformOriginX(const Length& v) { setTransformOrigin(TransformOrigin(v, transformOriginY(), transformOriginZ())); }
     void setTransformOriginY(const Length& v) { setTransformOrigin(TransformOrigin(transformOriginX(), v, transformOriginZ())); }
     void setTransformOriginZ(float f) { setTransformOrigin(TransformOrigin(transformOriginX(), transformOriginY(), f)); }
-    void setTransformOrigin(const TransformOrigin& o) { SET_VAR(rareNonInheritedData.access()->m_transform, m_origin, o); }
+    void setTransformOrigin(const TransformOrigin& o) { SET_NESTED_VAR(rareNonInheritedData, m_transform, m_origin, o); }
     void setTranslate(PassRefPtr<TranslateTransformOperation> v) { rareNonInheritedData.access()->m_transform.access()->m_translate = v; }
     void setRotate(PassRefPtr<RotateTransformOperation> v) { rareNonInheritedData.access()->m_transform.access()->m_rotate = v; }
     void setScale(PassRefPtr<ScaleTransformOperation> v) { rareNonInheritedData.access()->m_transform.access()->m_scale = v; }
 
     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 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); }
@@ skipping 599 matching lines @@
 }
 
 inline bool ComputedStyle::hasPseudoElementStyle() const
 {
     return noninherited_flags.pseudoBits & PSEUDO_ELEMENT_MASK;
 }
 
 } // namespace blink
 
 #endif // ComputedStyle_h