[WIP] Web Animations API: Constructing an Animation from partial keyframes throws a JS exception

Source/core/animation/KeyframeEffectModel.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 90 matching lines @@
     }
 
     // AnimationEffect implementation.
     virtual PassOwnPtr<CompositableValueList> sample(int iteration, double fraction) const OVERRIDE;
 
     // FIXME: Implement setFrames()
     const KeyframeVector& getFrames() const { return m_keyframes; }
 
     virtual bool isKeyframeEffectModel() const OVERRIDE { return true; }
 
+    bool isReplaceOnly();
+
     PropertySet properties() const;
 
     class PropertySpecificKeyframe {
     public:
         PropertySpecificKeyframe(double offset, PassRefPtr<TimingFunction> easing, const AnimatableValue*, CompositeOperation);
         double offset() const { return m_offset; }
         const TimingFunction* easing() const { return m_easing.get(); }
         const CompositableValue* value() const { return m_value.get(); }
         PassOwnPtr<PropertySpecificKeyframe> cloneWithOffset(double offset) const;
     private:
@@ skipping 41 matching lines @@
     mutable OwnPtr<KeyframeGroupMap> m_keyframeGroups;
 
     friend class KeyframeEffectModelTest;
 };
 
 DEFINE_TYPE_CASTS(KeyframeEffectModel, AnimationEffect, value, value->isKeyframeEffectModel(), value.isKeyframeEffectModel());
 
 } // namespace WebCore
 
 #endif // KeyframeEffectModel_h