Prepare for responsive CSS animations.

Source/core/animation/StringKeyframe.h

Index: Source/core/animation/StringKeyframe.h
diff --git a/Source/core/animation/StringKeyframe.h b/Source/core/animation/StringKeyframe.h
index 1ec0ea967d091b8f399450b2ba725f8764ebbf00..6f7c7b23a43dc2a58aff5d8b5fdd7b843d7e63af 100644
--- a/Source/core/animation/StringKeyframe.h
+++ b/Source/core/animation/StringKeyframe.h
@@ -19,6 +19,7 @@ public:
         return adoptRefWillBeNoop(new StringKeyframe);
     }
     void setPropertyValue(CSSPropertyID, const String& value, StyleSheetContents*);
+    void setPropertyValue(CSSPropertyID, PassRefPtr<CSSValue>);
     void clearPropertyValue(CSSPropertyID property) { m_propertySet->removeProperty(property); }
     CSSValue* propertyValue(CSSPropertyID property) const
     {
@@ -36,7 +37,9 @@ public:
         PropertySpecificKeyframe(double offset, PassRefPtr<TimingFunction> easing, CSSValue*, AnimationEffect::CompositeOperation);
 
         CSSValue* value() const { return m_value.get(); }
+        void setEasing(PassRefPtrWillBeRawPtr<TimingFunction> easing) { m_easing = easing; }
         virtual const PassRefPtrWillBeRawPtr<AnimatableValue> getAnimatableValue() const override final { return m_animatableValueCache.get(); }
+        void setAnimatableValue(PassRefPtr<AnimatableValue>);
 
         virtual PassOwnPtrWillBeRawPtr<Keyframe::PropertySpecificKeyframe> neutralKeyframe(double offset, PassRefPtr<TimingFunction> easing) const override final;
         virtual PassRefPtrWillBeRawPtr<Interpolation> maybeCreateInterpolation(CSSPropertyID, blink::Keyframe::PropertySpecificKeyframe& end, Element*) const override final;