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 da2b9b77e1cc628ceec8c8a291e5d6fa8e545680..03ec3d89896b3d9d3f9883d3745f3576939cc452 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyle.cpp
+++ b/third_party/WebKit/Source/core/style/ComputedStyle.cpp
@@ -1042,7 +1042,11 @@ 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 !=