Composited Animations: Support --disable-threaded-animation in new animation system.

Source/core/animation/AnimationTimeline.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 59 matching lines @@
     , m_zeroTimeInitialized(false)
     , m_outdatedAnimationCount(0)
     , m_playbackRate(1)
     , m_lastCurrentTimeInternal(0)
 {
     if (!timing)
         m_timing = adoptPtrWillBeNoop(new AnimationTimelineTiming(this));
     else
         m_timing = timing;
 
-    if (RuntimeEnabledFeatures::compositorAnimationTimelinesEnabled() && Platform::current()->compositorSupport())
+    if (RuntimeEnabledFeatures::compositorAnimationTimelinesEnabled() && Platform::current()->isThreadedAnimationEnabled()) {
+        ASSERT(Platform::current()->compositorSupport());
         m_compositorTimeline = adoptPtr(Platform::current()->compositorSupport()->createAnimationTimeline());
+    }
 
     ASSERT(document);
 }
 
 AnimationTimeline::~AnimationTimeline()
 {
 #if !ENABLE(OILPAN)
     for (const auto& animation : m_animations)
         animation->detachFromTimeline();
 #endif
@@ skipping 233 matching lines @@
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_document);
     visitor->trace(m_timing);
     visitor->trace(m_animationsNeedingUpdate);
     visitor->trace(m_animations);
 #endif
 }
 
 } // namespace