Update animation when changes in animation keyframes are detected.

Source/core/animation/Animation.h

Index: Source/core/animation/Animation.h
diff --git a/Source/core/animation/Animation.h b/Source/core/animation/Animation.h
index 9adaffa9565af37bd4962687dc6c753185b9538e..903fbf48700f7313d0142ca7a4d292255825f27f 100644
--- a/Source/core/animation/Animation.h
+++ b/Source/core/animation/Animation.h
@@ -66,6 +66,7 @@ public:
     bool affects(CSSPropertyID) const;
     const AnimationEffect* effect() const { return m_effect.get(); }
     AnimationEffect* effect() { return m_effect.get(); }
+    void setEffect(PassRefPtrWillBeRawPtr<AnimationEffect> effect) { m_effect = effect; }
     Priority priority() const { return m_priority; }
     Element* target() const { return m_target; }