Incorporate ComputedStyle::hasTransform when diffing transform styles.

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

Index: third_party/WebKit/Source/core/style/ComputedStyle.cpp
diff --git a/third_party/WebKit/Source/core/style/ComputedStyle.cpp b/third_party/WebKit/Source/core/style/ComputedStyle.cpp
index 5dd19f8a4ccbf6b31a18c234b14f22b4c6f70557..515e7e830332126a5ef0a529246acbdf3df656b4 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyle.cpp
+++ b/third_party/WebKit/Source/core/style/ComputedStyle.cpp
@@ -1027,7 +1027,11 @@ void ComputedStyle::updatePropertySpecificDifferences(
     diff.setZIndexChanged();
 
   if (m_rareNonInheritedData.get() != other.m_rareNonInheritedData.get()) {
-    if (!transformDataEquivalent(other) ||
+    // It's possible for the old and new style transform data to be equivalent
+    // while hasTransform() differs, as it checks a number of conditions aside
+    // from just the matrix, including but not limited to animation state.
+    if (hasTransform() != other.hasTransform() ||
+        !transformDataEquivalent(other) ||
         m_rareNonInheritedData->m_perspective !=
             other.m_rareNonInheritedData->m_perspective ||
         m_rareNonInheritedData->m_perspectiveOrigin !=