Handling transition animation between non-interpolable values.

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

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 27 matching lines @@
 class AnimatableLengthSize final : public AnimatableValue {
 public:
     ~AnimatableLengthSize() override { }
     static PassRefPtr<AnimatableLengthSize> create(PassRefPtr<AnimatableValue> width, PassRefPtr<AnimatableValue> height)
     {
         return adoptRef(new AnimatableLengthSize(width, height));
     }
     const AnimatableValue* width() const { return m_width.get(); }
     const AnimatableValue* height() const { return m_height.get(); }
 
+    bool usesDefaultInterpolationWith(const AnimatableValue*) const override;
+
 protected:
     PassRefPtr<AnimatableValue> interpolateTo(const AnimatableValue*, double fraction) const override;
 
 private:
     AnimatableLengthSize(PassRefPtr<AnimatableValue> width, PassRefPtr<AnimatableValue> height)
         : m_width(width)
         , m_height(height)
     {
     }
     AnimatableType type() const override { return TypeLengthSize; }
     bool equalTo(const AnimatableValue*) const override;
 
     RefPtr<AnimatableValue> m_width;
     RefPtr<AnimatableValue> m_height;
 };
 
 DEFINE_ANIMATABLE_VALUE_TYPE_CASTS(AnimatableLengthSize, isLengthSize());
 
 } // namespace blink
 
 #endif // AnimatableLengthSize_h