Web Animations: Introduce ActiveAnimations and AnimationStack

Source/core/animation/DocumentTimeline.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef DocumentTimeline_h
 #define DocumentTimeline_h
 
+#include "core/animation/ActiveAnimations.h"
 #include "core/animation/Player.h"
+#include "core/dom/Element.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class Document;
 class TimedItem;
 
 // DocumentTimeline is constructed and owned by Document, and tied to its lifecycle.
 class DocumentTimeline : public RefCounted<DocumentTimeline> {
 
 public:
     static PassRefPtr<DocumentTimeline> create(Document*);
     void serviceAnimations(double);
     PassRefPtr<Player> play(TimedItem*);
     double currentTime() { return m_currentTime; }
     void pauseAnimationsForTesting(double);
+    AnimationStack* animationStack(const Element* element) const
+    {
+        if (ActiveAnimations* animations = element->activeAnimations())
+            return animations->defaultStack();
+        return 0;
+    }
 
 private:
     DocumentTimeline(Document*);
     double m_currentTime;
     Document* m_document;
     Vector<RefPtr<Player> > m_players;
 };
 
 } // namespace
 
 #endif