Revert "Web Animations: Introduce String based KeyframeEffectModel"

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 "CSSPropertyNames.h"
 #include "core/animation/InterpolableValue.h"
 #include "heap/Handle.h"
@@ skipping 26 matching lines @@
     mutable int m_cachedIteration;
     mutable OwnPtrWillBeMember<InterpolableValue> m_cachedValue;
 
     Interpolation(PassOwnPtrWillBeRawPtr<InterpolableValue> start, PassOwnPtrWillBeRawPtr<InterpolableValue> end);
 
 private:
     InterpolableValue* getCachedValueForTesting() const { return m_cachedValue.get(); }
 
     friend class AnimationInterpolableValueTest;
     friend class AnimationInterpolationEffectTest;
+
 };
 
 class StyleInterpolation : public Interpolation {
 public:
     // 1) convert m_cachedValue into an X
     // 2) shove X into StyleResolverState
     // X can be:
     // (1) a CSSValue (and applied via StyleBuilder::applyProperty)
     // (2) an AnimatableValue (and applied via // AnimatedStyleBuilder::applyProperty)
     // (3) a custom value that is inserted directly into the StyleResolverState.
@@ skipping 18 matching lines @@
 class LegacyStyleInterpolation : public StyleInterpolation {
 public:
     static PassRefPtrWillBeRawPtr<LegacyStyleInterpolation> create(PassRefPtrWillBeRawPtr<AnimatableValue> start, PassRefPtrWillBeRawPtr<AnimatableValue> end, CSSPropertyID id)
     {
         return adoptRefWillBeNoop(new LegacyStyleInterpolation(InterpolableAnimatableValue::create(start), InterpolableAnimatableValue::create(end), id));
     }
 
     virtual void apply(StyleResolverState&) const;
 
     virtual bool isLegacyStyleInterpolation() const OVERRIDE FINAL { return true; }
-    PassRefPtr<AnimatableValue> currentValue() const
+    AnimatableValue* currentValue() const
     {
         InterpolableAnimatableValue* value = static_cast<InterpolableAnimatableValue*>(m_cachedValue.get());
         return value->value();
     }
 
     virtual void trace(Visitor*) OVERRIDE;
 
 private:
     LegacyStyleInterpolation(PassOwnPtrWillBeRawPtr<InterpolableValue> start, PassOwnPtrWillBeRawPtr<InterpolableValue> end, CSSPropertyID id)
         : StyleInterpolation(start, end, id)
     {
     }
 };
 
 DEFINE_TYPE_CASTS(StyleInterpolation, Interpolation, value, value->isStyleInterpolation(), value.isStyleInterpolation());
 DEFINE_TYPE_CASTS(LegacyStyleInterpolation, Interpolation, value, value->isLegacyStyleInterpolation(), value.isLegacyStyleInterpolation());
 
 }
 #endif