Ensure serviceOnNextFrame isn't put off indefinitely.

Source/core/animation/AnimationTimeline.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
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  *     * Redistributions in binary form must reproduce the above
@@ skipping 156 matching lines @@
 
     if (timeToNextEffect < s_minimumDelay) {
         m_timing->serviceOnNextFrame();
     } else if (timeToNextEffect != std::numeric_limits<double>::infinity()) {
         m_timing->wakeAfter(timeToNextEffect - s_minimumDelay);
     }
 }
 
 void AnimationTimeline::AnimationTimelineTiming::wakeAfter(double duration)
 {
+    double nextFireTime = m_timeline->currentTime() + duration;

[alancutter (OOO until 2018), 2015/08/17 07:30:36]

currentTime() is affected by m_playbackRate making it different to wall clock
time.
I suspect duration is in terms of wall clock time so you should probably use
document()->animationClock() here instead.

[dtapuska, 2015/08/17 17:50:44]

Acknowledged.

+    if (m_timer.isActive() && nextFireTime >= m_currentScheduledTime)

[dstockwell, 2015/08/17 08:05:36]

You should be able to retrieve the next fire time from the timer directly (see
TimerBase::nextFireInterval), and reduce the patch to this one line.

[dtapuska, 2015/08/17 17:50:44]

Done.

+        return;
+    m_currentScheduledTime = nextFireTime;
     m_timer.startOneShot(duration, FROM_HERE);
 }
 
 void AnimationTimeline::AnimationTimelineTiming::cancelWake()
 {
+    m_currentScheduledTime = std::numeric_limits<double>::infinity();
     m_timer.stop();
 }
 
 void AnimationTimeline::AnimationTimelineTiming::serviceOnNextFrame()
 {
     if (m_timeline->m_document && m_timeline->m_document->view())
         m_timeline->m_document->view()->scheduleAnimation();
 }
 
 DEFINE_TRACE(AnimationTimeline::AnimationTimelineTiming)
@@ skipping 131 matching lines @@
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_document);
     visitor->trace(m_timing);
     visitor->trace(m_animationsNeedingUpdate);
     visitor->trace(m_animations);
 #endif
 }
 
 } // namespace