Add a comment to a subtle use of OwnPtr::release()

Source/core/animation/css/CSSAnimations.cpp

Index: Source/core/animation/css/CSSAnimations.cpp
diff --git a/Source/core/animation/css/CSSAnimations.cpp b/Source/core/animation/css/CSSAnimations.cpp
index b834812c8182db1b829f3afea65ff7c13546135c..5b39777840c06363a8eaf167bd1de5cb15d7832a 100644
--- a/Source/core/animation/css/CSSAnimations.cpp
+++ b/Source/core/animation/css/CSSAnimations.cpp
@@ -223,6 +223,8 @@ void CSSAnimations::maybeApplyPendingUpdate(Element* element)
         HashSet<RefPtr<Player> > players;
         for (HashSet<RefPtr<InertAnimation> >::const_iterator animationsIter = iter->animations.begin(); animationsIter != iter->animations.end(); ++animationsIter) {
             const InertAnimation* inertAnimation = animationsIter->get();
+            // The event delegate is set on the the first animation only. We
+            // rely on the behavior of OwnPtr::release() to achieve this.
             RefPtr<Animation> animation = Animation::create(element, inertAnimation->effect(), inertAnimation->specified(), eventDelegate.release());
             players.add(element->document().timeline()->play(animation.get()));
         }