Incorporate ComputedStyle::hasTransform when diffing transform styles.

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
@@ skipping 3265 matching lines @@
     return hasTransformOperations() || hasOffset() ||
            hasCurrentTransformAnimation() || translate() || rotate() || scale();
   }
   bool hasTransformOperations() const {
     return !m_rareNonInheritedData->m_transform->m_operations.operations()
                 .isEmpty();
   }
   ETransformStyle3D usedTransformStyle3D() const {
     return hasGroupingProperty() ? TransformStyle3DFlat : transformStyle3D();
   }
+  // Returns whether the transform operations for |otherStyle| differ from the
+  // operations for this style instance. Note that callers may want to also
+  // check hasTransform(), as it is possible for two styles to have matching
+  // transform operations but differ in other transform-impacting style
+  // respects.
   bool transformDataEquivalent(const ComputedStyle& otherStyle) const {
     return m_rareNonInheritedData->m_transform ==
            otherStyle.m_rareNonInheritedData->m_transform;
   }
   bool preserves3D() const {
     return usedTransformStyle3D() != TransformStyle3DFlat;
   }
   enum ApplyTransformOrigin { IncludeTransformOrigin, ExcludeTransformOrigin };
   enum ApplyMotionPath { IncludeMotionPath, ExcludeMotionPath };
   enum ApplyIndependentTransformProperties {
@@ skipping 488 matching lines @@
   m_nonInheritedData.m_pseudoBits |= 1 << (pseudo - FirstPublicPseudoId);
 }
 
 inline bool ComputedStyle::hasPseudoElementStyle() const {
   return m_nonInheritedData.m_pseudoBits & ElementPseudoIdMask;
 }
 
 }  // namespace blink
 
 #endif  // ComputedStyle_h