Update a result vector when sampling animation effects.

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 f7aa908c6800756d9956d736501d9bcfd43463c5..ec809aa649f2d47de64de036e34dbcd7d3637dc2 100644
--- a/Source/core/animation/KeyframeEffectModel.h
+++ b/Source/core/animation/KeyframeEffectModel.h
@@ -86,7 +86,7 @@ public:
     }
 
     // AnimationEffect implementation.
-    virtual PassOwnPtrWillBeRawPtr<WillBeHeapVector<RefPtrWillBeMember<Interpolation>>> sample(int iteration, double fraction, double iterationDuration) const override;
+    virtual void sample(int iteration, double fraction, double iterationDuration, OwnPtrWillBeRawPtr<WillBeHeapVector<RefPtrWillBeMember<Interpolation>>>&) const override;
 
     virtual bool isKeyframeEffectModel() const override { return true; }