Web Animations: Fix effect change calculation when player is cancelled but not held

Source/core/animation/AnimationPlayer.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 322 matching lines @@
             m_timeline->document()->enqueueAnimationFrameEvent(event.release());
         }
         m_finished = finished();
     }
     return !m_finished || m_content->isCurrent() || m_content->isInEffect();
 }
 
 double AnimationPlayer::timeToEffectChange()
 {
     ASSERT(!m_outdated);
-    if (!m_content || m_held)
+    if (m_held || !hasStartTime())
         return std::numeric_limits<double>::infinity();
+    if (!m_content)
+        return -currentTime() / m_playbackRate;
     if (m_playbackRate > 0)
         return m_content->timeToForwardsEffectChange() / m_playbackRate;
-    return m_content->timeToReverseEffectChange() / std::abs(m_playbackRate);
+    return m_content->timeToReverseEffectChange() / -m_playbackRate;
 }
 
 void AnimationPlayer::cancel()
 {
     if (!m_content)
         return;
 
     ASSERT(m_content->player() == this);
     m_content->detach();
     m_content = nullptr;
@@ skipping 13 matching lines @@
 {
     RELEASE_ASSERT(!paused());
     updateTimingState(pauseTime);
     if (!m_isPausedForTesting && hasActiveAnimationsOnCompositor())
         toAnimation(m_content.get())->pauseAnimationForTestingOnCompositor(currentTime());
     m_isPausedForTesting = true;
     pause();
 }
 
 } // namespace