Fix a bug that could occasionaly cause setInterval to stop

third_party/WebKit/Source/platform/Timer.cpp

 /*
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 79 matching lines @@
 
 WebTaskRunner* TimerBase::timerTaskRunner() const
 {
     return m_webTaskRunner;
 }
 
 void TimerBase::setNextFireTime(double now, double delay)
 {
     ASSERT(m_thread == currentThread());
 
-    double newTime = now + delay;
+    m_nextFireTime = now + delay;
+    if (m_cancellableTimerTask)
+        m_cancellableTimerTask->cancel();
+    m_cancellableTimerTask = new CancellableTimerTask(this);
 
-    if (m_nextFireTime != newTime) {
-        m_nextFireTime = newTime;
-        if (m_cancellableTimerTask)
-            m_cancellableTimerTask->cancel();
-        m_cancellableTimerTask = new CancellableTimerTask(this);
-
-        double delayMs = 1000.0 * (newTime - now);
-        timerTaskRunner()->postDelayedTask(m_location, m_cancellableTimerTask, delayMs);
-    }
+    double delayMs = 1000.0 * delay;
+    timerTaskRunner()->postDelayedTask(m_location, m_cancellableTimerTask, delayMs);
 }
 
 NO_LAZY_SWEEP_SANITIZE_ADDRESS
 void TimerBase::runInternal()
 {
     if (!canFire())
         return;
 
     TRACE_EVENT0("blink", "TimerBase::run");
 #if DCHECK_IS_ON()
     DCHECK_EQ(m_thread, currentThread()) << "Timer posted by " << m_location.function_name() << " " << m_location.file_name() << " was run on a different thread";
 #endif
     TRACE_EVENT_SET_SAMPLING_STATE("blink", "BlinkInternal");
 
     if (m_repeatInterval) {
         double now = timerMonotonicallyIncreasingTime();
         // This computation should be drift free, and it will cope if we miss a beat,
         // which can easily happen if the thread is busy.  It will also cope if we get
         // called slightly before m_unalignedNextFireTime, which can happen due to lack
         // of timer precision.
         double intervalToNextFireTime = m_repeatInterval - fmod(now - m_nextFireTime, m_repeatInterval);
-        setNextFireTime(timerMonotonicallyIncreasingTime(), intervalToNextFireTime);
+        setNextFireTime(now, intervalToNextFireTime);
     } else {
         m_nextFireTime = 0;
     }
     fired();
     TRACE_EVENT_SET_SAMPLING_STATE("blink", "Sleeping");
 }
 
 bool TimerBase::Comparator::operator()(const TimerBase* a, const TimerBase* b) const
 {
     return a->m_nextFireTime < b->m_nextFireTime;
 }
 
 // static
 WebTaskRunner* TimerBase::UnthrottledWebTaskRunner()
 {
     return Platform::current()->currentThread()->getWebTaskRunner();
 }
 
 double TimerBase::timerMonotonicallyIncreasingTime() const
 {
     return timerTaskRunner()->monotonicallyIncreasingVirtualTimeSeconds();
 }
 
 } // namespace blink