Add TransitionKeyframe class for CSS Transition refactor

third_party/WebKit/Source/core/animation/Keyframe.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 Keyframe_h
 #define Keyframe_h
 
 #include "core/CoreExport.h"
 #include "core/animation/AnimationEffectReadOnly.h"
 #include "core/animation/EffectModel.h"
@@ skipping 41 matching lines @@
 
   virtual PassRefPtr<Keyframe> clone() const = 0;
   PassRefPtr<Keyframe> cloneWithOffset(double offset) const {
     RefPtr<Keyframe> theClone = clone();
     theClone->setOffset(offset);
     return theClone.release();
   }
 
   virtual bool isAnimatableValueKeyframe() const { return false; }
   virtual bool isStringKeyframe() const { return false; }
+  virtual bool isTransitionKeyframe() const { return false; }
 
   // Represents a property-value pair in a keyframe.
   class PropertySpecificKeyframe : public RefCounted<PropertySpecificKeyframe> {
     USING_FAST_MALLOC(PropertySpecificKeyframe);
     WTF_MAKE_NONCOPYABLE(PropertySpecificKeyframe);
 
    public:
     virtual ~PropertySpecificKeyframe() {}
     double offset() const { return m_offset; }
     TimingFunction& easing() const { return *m_easing; }
@@ skipping 14 matching lines @@
         const ComputedStyle* parentStyle) const {
       return false;
     }
     virtual PassRefPtr<AnimatableValue> getAnimatableValue() const = 0;
 
     virtual bool isAnimatableValuePropertySpecificKeyframe() const {
       return false;
     }
     virtual bool isCSSPropertySpecificKeyframe() const { return false; }
     virtual bool isSVGPropertySpecificKeyframe() const { return false; }
+    virtual bool isTransitionPropertySpecificKeyframe() const { return false; }
 
     virtual PassRefPtr<PropertySpecificKeyframe> neutralKeyframe(
         double offset,
         PassRefPtr<TimingFunction> easing) const = 0;
     virtual PassRefPtr<Interpolation> createInterpolation(
         PropertyHandle,
         const Keyframe::PropertySpecificKeyframe& end) const;
 
    protected:
     PropertySpecificKeyframe(double offset,
@@ skipping 21 matching lines @@
   double m_offset;
   EffectModel::CompositeOperation m_composite;
   RefPtr<TimingFunction> m_easing;
 };
 
 using PropertySpecificKeyframe = Keyframe::PropertySpecificKeyframe;
 
 }  // namespace blink
 
 #endif  // Keyframe_h