Web Animations CSS: Unfreeze AnimationClock if sampling timelines does not trigger style recalc

Source/core/animation/TimedItemTest.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 57 matching lines @@
     {
         return adoptRef(new TestTimedItem(specified, new TestTimedItemEventDelegate()));
     }
 
     void updateInheritedTime(double time)
     {
         m_eventDelegate->reset();
         TimedItem::updateInheritedTime(time);
     }
 
-    void updateChildrenAndEffects() const FINAL OVERRIDE { }
+    bool updateChildrenAndEffects() const FINAL OVERRIDE { return false; }
     void willDetach() { }
     TestTimedItemEventDelegate* eventDelegate() { return m_eventDelegate; }
     double calculateTimeToEffectChange(double inheritedTime, double activeTime, Phase) const FINAL OVERRIDE { return -1; }
 
 private:
     TestTimedItem(const Timing& specified, TestTimedItemEventDelegate* eventDelegate)
         : TimedItem(specified, adoptPtr(eventDelegate))
         , m_eventDelegate(eventDelegate)
     {
     }
@@ skipping 479 matching lines @@
     // After end
     timedItem->updateInheritedTime(3.5);
     ASSERT_TRUE(timedItem->eventDelegate()->eventTriggered());
     EXPECT_TRUE(timedItem->eventDelegate()->phaseChanged());
     EXPECT_FALSE(timedItem->eventDelegate()->iterationChanged());
 
     timedItem->updateInheritedTime(3.6);
     ASSERT_FALSE(timedItem->eventDelegate()->eventTriggered());
 }
 }