Don't squash layers with non-translation transforms.

third_party/WebKit/Source/platform/graphics/SquashingDisallowedReasons.cpp

Index: third_party/WebKit/Source/platform/graphics/SquashingDisallowedReasons.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/SquashingDisallowedReasons.cpp b/third_party/WebKit/Source/platform/graphics/SquashingDisallowedReasons.cpp
index 54728f6eca87da198eaa713253f80e6a101d4213..de6fd4eedaebba25d99d27c91fd8928d7c5569f0 100644
--- a/third_party/WebKit/Source/platform/graphics/SquashingDisallowedReasons.cpp
+++ b/third_party/WebKit/Source/platform/graphics/SquashingDisallowedReasons.cpp
@@ -57,6 +57,9 @@ const SquashingDisallowedReasonStringMap kSquashingDisallowedReasonStringMap[] =
     { SquashingDisallowedReasonRenderingContextMismatch,
         "squashingLayerRenderingContextMismatch",
         "Cannot squash layers with different 3D contexts." },
+    { SquashingDisallowedReasonNonTranslationTransform,
+        "SquashingDisallowedReasonNonTranslationTransform",
+        "Cannot squash layers with transforms that are not identity or translation." },
 };
 
 const size_t kNumberOfSquashingDisallowedReasons = WTF_ARRAY_LENGTH(kSquashingDisallowedReasonStringMap);