Incorporate ComputedStyle::hasTransform when diffing transform styles.

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

Index: third_party/WebKit/Source/core/style/ComputedStyle.h
diff --git a/third_party/WebKit/Source/core/style/ComputedStyle.h b/third_party/WebKit/Source/core/style/ComputedStyle.h
index 7ec9c51f4b883e324eb9c95b7648f71c4b11c2e2..9c379135a2c7b6fe89a18b665b7bd39c69166915 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyle.h
+++ b/third_party/WebKit/Source/core/style/ComputedStyle.h
@@ -3283,6 +3283,11 @@ class CORE_EXPORT ComputedStyle : public ComputedStyleBase,
   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;