Allow pausing paused animations for testing

third_party/WebKit/Source/core/animation/Animation.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 1062 matching lines @@
 
 void Animation::addedEventListener(
     const AtomicString& eventType,
     RegisteredEventListener& registeredListener) {
   EventTargetWithInlineData::addedEventListener(eventType, registeredListener);
   if (eventType == EventTypeNames::finish)
     UseCounter::count(getExecutionContext(), UseCounter::AnimationFinishEvent);
 }
 
 void Animation::pauseForTesting(double pauseTime) {
-  RELEASE_ASSERT(!paused());
   setCurrentTimeInternal(pauseTime, TimingUpdateOnDemand);
   if (hasActiveAnimationsOnCompositor())
     toKeyframeEffectReadOnly(m_content.get())
         ->pauseAnimationForTestingOnCompositor(currentTimeInternal());
   m_isPausedForTesting = true;
   pause();
 }
 
 void Animation::setEffectSuppressed(bool suppressed) {
   m_effectSuppressed = suppressed;
@@ skipping 57 matching lines @@
   DCHECK(!m_compositorPlayer);
 }
 
 void Animation::CompositorAnimationPlayerHolder::detach() {
   DCHECK(m_compositorPlayer);
   m_compositorPlayer->setAnimationDelegate(nullptr);
   m_animation = nullptr;
   m_compositorPlayer.reset();
 }
 }  // namespace blink