Remove more oilpan.

sky/engine/core/animation/KeyframeEffectModel.h

Index: sky/engine/core/animation/KeyframeEffectModel.h
diff --git a/sky/engine/core/animation/KeyframeEffectModel.h b/sky/engine/core/animation/KeyframeEffectModel.h
index 50f006083615b1cb81e4a180aa98c0fbe727c99a..3a856fc7868af7cb9e6d6025be4dc03305095006 100644
--- a/sky/engine/core/animation/KeyframeEffectModel.h
+++ b/sky/engine/core/animation/KeyframeEffectModel.h
@@ -55,7 +55,7 @@ public:
     // FIXME: Implement accumulation.
 
     typedef Vector<OwnPtr<Keyframe::PropertySpecificKeyframe> > PropertySpecificKeyframeVector;
-    class PropertySpecificKeyframeGroup : public DummyBase<PropertySpecificKeyframeGroup> {
+    class PropertySpecificKeyframeGroup {
     public:
         void appendKeyframe(PassOwnPtr<Keyframe::PropertySpecificKeyframe>);
         const PropertySpecificKeyframeVector& keyframes() const { return m_keyframes; }