Ensure baseComputedStyle optimisation is cleared during registered custom property animations

third_party/WebKit/Source/core/animation/AnimationClock.cpp

 /*
  * Copyright (c) 2014, 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 34 matching lines @@
 
 unsigned AnimationClock::s_currentlyRunningTask = 0;
 
 void AnimationClock::updateTime(double time) {
   if (time > m_time)
     m_time = time;
   m_taskForWhichTimeWasCalculated = s_currentlyRunningTask;
 }
 
 double AnimationClock::currentTime() {
-  if (m_taskForWhichTimeWasCalculated != s_currentlyRunningTask) {
+  if (m_monotonicallyIncreasingTime &&
+      m_taskForWhichTimeWasCalculated != s_currentlyRunningTask) {
     const double currentTime = m_monotonicallyIncreasingTime();
     if (m_time < currentTime) {
       // Advance to the first estimated frame after the current time.
       const double frameShift =
           fmod(currentTime - m_time, approximateFrameTime);
       const double newTime = currentTime + (approximateFrameTime - frameShift);
       DCHECK_GE(newTime, currentTime);
       DCHECK_LE(newTime, currentTime + approximateFrameTime);
       updateTime(newTime);
     } else {
       m_taskForWhichTimeWasCalculated = s_currentlyRunningTask;
     }
   }
   return m_time;
 }
 
 void AnimationClock::resetTimeForTesting(double time) {
   m_time = time;
   m_taskForWhichTimeWasCalculated = 0;
   s_currentlyRunningTask = 0;
 }
 
 }  // namespace blink