Web Animations CSS: Fix DocumentTimeline::numberOfActiveAnimationsForTesting()

Source/core/animation/DocumentTimeline.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 140 matching lines @@
     Vector<EventToDispatch> events = m_events;
     m_events.clear();
     for (size_t i = 0; i < events.size(); i++)
         events[i].target->dispatchEvent(events[i].event.release());
 }
 
 size_t DocumentTimeline::numberOfActiveAnimationsForTesting() const
 {
     // Includes all players whose directly associated timed items
     // are current or in effect.
-    return isNull(m_zeroTime) ? 0 : m_players.size();
+    if (isNull(m_zeroTime))
+        return 0;
+    size_t count = 0;
+    for (size_t i = 0; i < m_players.size(); ++i) {
+        const TimedItem* timedItem = m_players[i]->source();
+        count += (timedItem && (timedItem->isCurrent() || timedItem->isInEffect()));
+    }
+    return count;
 }
 
 } // namespace