Web Animations CSS: Snapshot missing start/end Keyframes and remove duplicates

Source/core/animation/KeyframeAnimationEffect.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 33 matching lines @@
 
 typedef HashSet<CSSPropertyID> PropertySet;
 
 // Represents the keyframes set through the API.
 class Keyframe : public RefCounted<Keyframe> {
 public:
     static PassRefPtr<Keyframe> create()
     {
         return adoptRef(new Keyframe);
     }
+    static bool compareOffsets(const RefPtr<Keyframe>& a, const RefPtr<Keyframe>& b)
+    {
+        return a->offset() < b->offset();
+    }
     void setOffset(double offset) { m_offset = offset; }
     double offset() const { return m_offset; }
     void setComposite(AnimationEffect::CompositeOperation composite) { m_composite = composite; }
     AnimationEffect::CompositeOperation composite() const { return m_composite; }
     void setPropertyValue(CSSPropertyID, const AnimatableValue*);
     const AnimatableValue* propertyValue(CSSPropertyID) const;
     PropertySet properties() const;
 private:
     Keyframe();
     double m_offset;
@@ skipping 52 matching lines @@
     // The spec describes filtering the normalized keyframes at sampling time
     // to get the 'property-specific keyframes'. For efficiency, we cache the
     // property-specific lists.
     typedef HashMap<CSSPropertyID, OwnPtr<PropertySpecificKeyframeGroup> > KeyframeGroupMap;
     OwnPtr<KeyframeGroupMap> m_keyframeGroups;
 };
 
 } // namespace WebCore
 
 #endif // KeyframeAnimationEffect_h