Web-Animations: Implement idle state for AnimationPlayers

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 175 matching lines @@
     else if (m_sampledEffect)
         const_cast<Animation*>(this)->clearEffects();
 }
 
 double Animation::calculateTimeToEffectChange(bool forwards, double localTime, double timeToNextIteration) const
 {
     const double start = startTimeInternal() + specifiedTiming().startDelay;
     const double end = start + activeDurationInternal();
 
     switch (phase()) {
+    case PhaseNone:
+        return std::numeric_limits<double>::infinity();
     case PhaseBefore:
         ASSERT(start >= localTime);
         return forwards
             ? start - localTime
             : std::numeric_limits<double>::infinity();
     case PhaseActive:
         if (forwards && hasActiveAnimationsOnCompositor()) {
             ASSERT(specifiedTiming().playbackRate == 1);
             // Need service to apply fill / fire events.
             const double timeToEnd = end - localTime;
@@ skipping 101 matching lines @@
 
 void Animation::trace(Visitor* visitor)
 {
     visitor->trace(m_target);
     visitor->trace(m_effect);
     visitor->trace(m_sampledEffect);
     AnimationNode::trace(visitor);
 }
 
 } // namespace blink