Handling transition animation between non-interpolable values.

third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.cpp

Index: third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.cpp
diff --git a/third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.cpp b/third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.cpp
index 67647d335dc27e152c3937d6ff5d7ae7871b7d06..8d552f0c78646f4652b0796f42a3e02c9a3078c3 100644
--- a/third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.cpp
+++ b/third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.cpp
@@ -46,4 +46,11 @@ bool AnimatableLengthSize::equalTo(const AnimatableValue* value) const
     return width()->equals(lengthSize->width()) && height()->equals(lengthSize->height());
 }
 
+bool AnimatableLengthSize::usesDefaultInterpolationWith(const AnimatableValue* other) const
+{
+    const AnimatableLengthSize* lengthSize = toAnimatableLengthSize(other);
+    return usesDefaultInterpolation(width(), lengthSize->width())
+        || usesDefaultInterpolation(height(), lengthSize->height());
+}
+
 } // namespace blink