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..6dd1bca2a8b3bef2601b9ccd28d5751621bf6c04 100644
--- a/Source/core/animation/KeyframeEffectModel.h
+++ b/Source/core/animation/KeyframeEffectModel.h
@@ -109,6 +109,11 @@ public:
         ensureInterpolationEffect(element);
     }
 
+    void setDeferredInterpolationsOutdated(bool outdated)
+    {
+        m_interpolationEffect->setDeferredInterpolationsOutdated(outdated);
+    }
+
     static KeyframeVector normalizedKeyframesForInspector(const KeyframeVector& keyframes) { return normalizedKeyframes(keyframes); }
 
 protected:
@@ -178,6 +183,16 @@ 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; }