Prepare for responsive CSS animations.

Source/core/animation/KeyframeEffectModel.h

Index: Source/core/animation/KeyframeEffectModel.h
diff --git a/Source/core/animation/KeyframeEffectModel.h b/Source/core/animation/KeyframeEffectModel.h
index 8029b3c99d2ce7c6141e352cc6c739225e780a3e..1239dd11f550c9bd6729560a491498ed4f025a67 100644
--- a/Source/core/animation/KeyframeEffectModel.h
+++ b/Source/core/animation/KeyframeEffectModel.h
@@ -109,6 +109,10 @@ public:
         ensureInterpolationEffect(element);
     }
 
+    void setDeferredInterpolationsOutdated() { m_interpolationEffect->setDeferredInterpolationsOutdated(); }
+    void snapshotCompositableProperties(const Element*, const RenderStyle&);
+    bool snapshotCompositablePropertiesIfNeeded(const Element*, const RenderStyle&, const RenderStyle&);
+
     static KeyframeVector normalizedKeyframesForInspector(const KeyframeVector& keyframes) { return normalizedKeyframes(keyframes); }
 
 protected:
@@ -135,6 +139,8 @@ protected:
         ensureKeyframeGroups();
         return m_keyframeGroups->contains(property);
     }
+
+    void snapshotCompositableProperty(CSSPropertyID, const Element*, const RenderStyle&);
 };
 
 template <class Keyframe>
@@ -178,6 +184,16 @@ inline AnimatableValueKeyframeEffectModel* toAnimatableValueKeyframeEffectModel(
     return toAnimatableValueKeyframeEffectModel(toKeyframeEffectModelBase(base));
 }
 
+inline const StringKeyframeEffectModel* toStringKeyframeEffectModel(const AnimationEffect* base)
+{
+    return toStringKeyframeEffectModel(toKeyframeEffectModelBase(base));
+}
+
+inline StringKeyframeEffectModel* toStringKeyframeEffectModel(AnimationEffect* base)
+{
+    return toStringKeyframeEffectModel(toKeyframeEffectModelBase(base));
+}
+
 template <>
 inline bool KeyframeEffectModel<AnimatableValueKeyframe>::isAnimatableValueKeyframeEffectModel() const { return true; }