Allow transitions on background-size with positionally matched keywords

third_party/WebKit/Source/core/animation/animatable/AnimatableUnknown.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 41 matching lines @@
 
     CSSValue* toCSSValue() const { return m_value; }
     CSSValueID toCSSValueID() const { return toCSSPrimitiveValue(m_value.get())->getValueID(); }
 
 protected:
     PassRefPtr<AnimatableValue> interpolateTo(const AnimatableValue* value, double fraction) const override
     {
         return defaultInterpolateTo(this, value, fraction);
     }
 
-    bool usesDefaultInterpolationWith(const AnimatableValue*) const override { return true; }
+    bool usesDefaultInterpolationWith(const AnimatableValue*) const override;
 
 private:
     explicit AnimatableUnknown(CSSValue* value)
         : m_value(value)
     {
         ASSERT(m_value);
     }
     AnimatableType type() const override { return TypeUnknown; }
     bool equalTo(const AnimatableValue*) const override;
 
     const Persistent<CSSValue> m_value;
 };
 
 DEFINE_ANIMATABLE_VALUE_TYPE_CASTS(AnimatableUnknown, isUnknown());
 
 inline bool AnimatableUnknown::equalTo(const AnimatableValue* value) const
 {
     const AnimatableUnknown* unknown = toAnimatableUnknown(value);
     return m_value == unknown->m_value || m_value->equals(*unknown->m_value);
 }
 
+inline bool AnimatableUnknown::usesDefaultInterpolationWith(const AnimatableValue* value) const
+{
+    const AnimatableUnknown& unknown = toAnimatableUnknown(*value);
+    return !m_value->equals(*unknown.m_value);
+}
+
 } // namespace blink
 
 #endif // AnimatableUnknown_h