SVG: Moving animating <svg> to other iframe should not crash.

Source/core/svg/animation/SMILTimeContainer.cpp

 /*
  * Copyright (C) 2008 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 141 matching lines @@
     return m_pauseTime;
 }
 
 bool SMILTimeContainer::isStarted() const
 {
     return m_beginTime;
 }
 
 void SMILTimeContainer::begin()
 {
-    ASSERT(!m_beginTime);
+    RELEASE_ASSERT(!m_beginTime);
     double now = currentTime();
 
     // If 'm_presetStartTime' is set, the timeline was modified via setElapsed() before the document began.
     // In this case pass on 'seekToTime=true' to updateAnimations().
     m_beginTime = now - m_presetStartTime;
 #if !ENABLE(OILPAN)
     DiscardScope discardScope(m_ownerSVGElement);
 #endif
     SMILTime earliestFireTime = updateAnimations(SMILTime(m_presetStartTime), m_presetStartTime ? true : false);
     m_presetStartTime = 0;
@@ skipping 273 matching lines @@
             if (animDiscard->inDocument()) {
                 animDiscard->remove(IGNORE_EXCEPTION);
                 ASSERT(!animDiscard->inDocument());
             }
         }
     }
     return earliestFireTime;
 }
 
 }