Ensure serviceOnNextFrame isn't put off indefinitely.

Source/core/animation/AnimationTimeline.cpp

Index: Source/core/animation/AnimationTimeline.cpp
diff --git a/Source/core/animation/AnimationTimeline.cpp b/Source/core/animation/AnimationTimeline.cpp
index dd7057a56e7d7f72f0abb5483a5ef455c5fbf34a..1097ed035785183a14dc9c6945aea3ef87181b59 100644
--- a/Source/core/animation/AnimationTimeline.cpp
+++ b/Source/core/animation/AnimationTimeline.cpp
@@ -174,11 +174,16 @@ void AnimationTimeline::scheduleNextService()
 
 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();
 }