Hash iterators: Check for concurrent modification and fix 1 place where it happened

Source/core/animation/DocumentTimeline.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 80 matching lines @@
 
 void DocumentTimeline::serviceAnimations()
 {
     TRACE_EVENT0("webkit", "DocumentTimeline::serviceAnimations");
 
     m_timing->cancelWake();
     m_hasOutdatedAnimationPlayer = false;
 
     double timeToNextEffect = std::numeric_limits<double>::infinity();
     Vector<AnimationPlayer*> players;
-    for (HashSet<RefPtr<AnimationPlayer> >::iterator it = m_playersNeedingUpdate.begin(); it != m_playersNeedingUpdate.end(); ++it)
+    for (ListHashSet<RefPtr<AnimationPlayer> >::iterator it = m_playersNeedingUpdate.begin(); it != m_playersNeedingUpdate.end(); ++it)
         players.append(it->get());
 
     std::sort(players.begin(), players.end(), AnimationPlayer::hasLowerPriority);
 
     for (size_t i = 0; i < players.size(); ++i) {
         AnimationPlayer* player = players[i];
         if (player->update())
             timeToNextEffect = std::min(timeToNextEffect, player->timeToEffectChange());
         else
             m_playersNeedingUpdate.remove(player);
@@ skipping 40 matching lines @@
 }
 
 double DocumentTimeline::effectiveTime()
 {
     double time = currentTime();
     return std::isnan(time) ? 0 : time;
 }
 
 void DocumentTimeline::pauseAnimationsForTesting(double pauseTime)
 {
-    for (HashSet<RefPtr<AnimationPlayer> >::iterator it = m_playersNeedingUpdate.begin(); it != m_playersNeedingUpdate.end(); ++it)
+    for (ListHashSet<RefPtr<AnimationPlayer> >::iterator it = m_playersNeedingUpdate.begin(); it != m_playersNeedingUpdate.end(); ++it)
         (*it)->pauseForTesting(pauseTime);
     serviceAnimations();
 }
 
 void DocumentTimeline::setOutdatedAnimationPlayer(AnimationPlayer* player)
 {
     m_playersNeedingUpdate.add(player);
     m_hasOutdatedAnimationPlayer = true;
     if (m_document && m_document->page() && !m_document->page()->animator().isServicingAnimations())
         m_timing->serviceOnNextFrame();
 }
 
 size_t DocumentTimeline::numberOfActiveAnimationsForTesting() const
 {
     if (isNull(m_zeroTime))
         return 0;
     // Includes all players whose directly associated timed items
     // are current or in effect.
     if (isNull(m_zeroTime))
         return 0;
     size_t count = 0;
-    for (HashSet<RefPtr<AnimationPlayer> >::iterator it = m_playersNeedingUpdate.begin(); it != m_playersNeedingUpdate.end(); ++it) {
+    for (ListHashSet<RefPtr<AnimationPlayer> >::const_iterator it = m_playersNeedingUpdate.begin(); it != m_playersNeedingUpdate.end(); ++it) {
         const TimedItem* timedItem = (*it)->source();
         if ((*it)->hasStartTime())
             count += (timedItem && (timedItem->isCurrent() || timedItem->isInEffect()));
     }
     return count;
 }
 
 void DocumentTimeline::detachFromDocument() {
     m_document = 0;
 }
 
 } // namespace