optimizing layout performance when only transform3d matrix changed by

Source/core/rendering/style/RenderStyle.cpp

Index: Source/core/rendering/style/RenderStyle.cpp
===================================================================
--- Source/core/rendering/style/RenderStyle.cpp	(revision 169401)
+++ Source/core/rendering/style/RenderStyle.cpp	(working copy)
@@ -458,6 +458,11 @@
             // Don't return early here; instead take note of the type of
             // change, and deal with it when looking at compositing.
             changedContextSensitiveProperties |= ContextSensitivePropertyTransform;
+            // if only diff with transform3d parameters changed
+            if (transform().has3DOperation() && other->transform().has3DOperation()) {
+                changedContextSensitiveProperties |= ContextSensitivePropertyTransform3D;
+            }
+
         }
 
         // If the counter directives change, trigger a relayout to re-calculate counter values and rebuild the counter node tree.