Transitions: Downgrade transition to animation after it has finished

Source/core/animation/css/CSSAnimations.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 380 matching lines @@
     // have matching cancelled animation property IDs on the compositor.
     WillBeHeapHashMap<CSSPropertyID, std::pair<RefPtrWillBeMember<Animation>, double>> retargetedCompositorTransitions;
     for (CSSPropertyID id : update->cancelledTransitions()) {
         ASSERT(m_transitions.contains(id));
 
         RefPtrWillBeRawPtr<AnimationPlayer> player = m_transitions.take(id).player;
         Animation* animation = toAnimation(player->source());
         if (animation->hasActiveAnimationsOnCompositor(id) && update->newTransitions().find(id) != update->newTransitions().end() && !player->limited())
             retargetedCompositorTransitions.add(id, std::pair<RefPtrWillBeMember<Animation>, double>(animation, player->startTimeInternal()));
         player->cancel();
+        // after cancelation, transitions must be downgraded or they'll fail
+        // to be considered when retriggering themselves. This can happen if
+        // the transition is captured through getAnimationPlayers then played.
+        if (player->source() && player->source()->isAnimation())
+            toAnimation(player->source())->downgradeToNormalAnimation();
         player->update(TimingUpdateOnDemand);
     }
 
     for (CSSPropertyID id : update->finishedTransitions()) {
         // This transition can also be cancelled and finished at the same time
-        if (m_transitions.contains(id))
-            m_transitions.take(id);
+        if (m_transitions.contains(id)) {
+            RefPtrWillBeRawPtr<AnimationPlayer> player = m_transitions.take(id).player;
+            // Transition must be downgraded
+            if (player->source() && player->source()->isAnimation())
+                toAnimation(player->source())->downgradeToNormalAnimation();
+        }
     }
 
     for (const auto& entry : update->newTransitions()) {
         const CSSAnimationUpdate::NewTransition& newTransition = entry.value;
 
         RunningTransition runningTransition;
         runningTransition.from = newTransition.from;
         runningTransition.to = newTransition.to;
 
         CSSPropertyID id = newTransition.id;
@@ skipping 406 matching lines @@
     visitor->trace(m_activeInterpolationsForAnimations);
     visitor->trace(m_activeInterpolationsForTransitions);
     visitor->trace(m_newAnimations);
     visitor->trace(m_suppressedAnimationPlayers);
     visitor->trace(m_animationsWithUpdates);
     visitor->trace(m_animationsWithStyleUpdates);
 #endif
 }
 
 } // namespace blink