Web Animations: Overhaul and trace play state in AnimationPlayer

Source/core/animation/CompositorPendingAnimations.cpp

 /*
  * 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 104 matching lines @@
 
     // If not, go ahead and start any animations that were waiting.
     notifyCompositorAnimationStarted(monotonicallyIncreasingTime());
 
     ASSERT(m_pending.isEmpty());
     return false;
 }
 
 void CompositorPendingAnimations::notifyCompositorAnimationStarted(double monotonicAnimationStartTime)
 {
+    TRACE_EVENT0("blink", "CompositorPendingAnimations::notifyCompositorAnimationStarted");
     for (size_t i = 0; i < m_waitingForCompositorAnimationStart.size(); ++i) {
         AnimationPlayer* player = m_waitingForCompositorAnimationStart[i].get();
         if (player->hasStartTime())
             continue;
         player->notifyCompositorStartTime(monotonicAnimationStartTime - player->timeline()->zeroTime());
     }
 
     m_waitingForCompositorAnimationStart.clear();
 }
 
 void CompositorPendingAnimations::trace(Visitor* visitor)
 {
     visitor->trace(m_pending);
     visitor->trace(m_waitingForCompositorAnimationStart);
 }
 
 } // namespace