Discard SampledEffects on elements if they are redundant

third_party/WebKit/Source/core/animation/Interpolation.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef Interpolation_h
 #define Interpolation_h
 
 #include "core/CoreExport.h"
 #include "core/animation/InterpolableValue.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class PropertyHandle;
 
 // Represents an animation's effect between an adjacent pair of PropertySpecificKeyframes.
 class CORE_EXPORT Interpolation : public RefCounted<Interpolation> {
     WTF_MAKE_NONCOPYABLE(Interpolation);
 public:
     virtual ~Interpolation();
 
     virtual void interpolate(int iteration, double fraction);
 
     virtual bool isStyleInterpolation() const { return false; }
     virtual bool isInvalidatableInterpolation() const { return false; }
     virtual bool isLegacyStyleInterpolation() const { return false; }
 
     virtual PropertyHandle property() const = 0;
+    virtual bool dependsOnUnderlyingValue() const { return false; }
 
 protected:
     const OwnPtr<InterpolableValue> m_start;
     const OwnPtr<InterpolableValue> m_end;
 
     mutable double m_cachedFraction;
     mutable int m_cachedIteration;
     mutable OwnPtr<InterpolableValue> m_cachedValue;
 
     Interpolation(PassOwnPtr<InterpolableValue> start, PassOwnPtr<InterpolableValue> end);
 
 private:
     InterpolableValue* getCachedValueForTesting() const { return m_cachedValue.get(); }
 
     friend class AnimationInterpolableValueTest;
     friend class AnimationInterpolationEffectTest;
     friend class AnimationDoubleStyleInterpolationTest;
     friend class AnimationVisibilityStyleInterpolationTest;
 };
 
 using ActiveInterpolations = Vector<RefPtr<Interpolation>, 1>;
 
 } // namespace blink
 
 #endif // Interpolation_h