[blink] Support moving timers between WebTaskRunners

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 67 matching lines @@
 }
 
 double TimerBase::nextFireInterval() const {
   ASSERT(isActive());
   double current = timerMonotonicallyIncreasingTime();
   if (m_nextFireTime < current)
     return 0;
   return m_nextFireTime - current;
 }
 
+void TimerBase::moveToNewTaskRunner(WebTaskRunner* taskRunner) {
+#if DCHECK_IS_ON()
+  DCHECK_EQ(m_thread, currentThread());
+  DCHECK(taskRunner->runsTasksOnCurrentThread());
+#endif
+  // If the underlying task runner stays the same, ignore it.
+  if (m_webTaskRunner->toSingleThreadTaskRunner() ==
+      taskRunner->toSingleThreadTaskRunner()) {
+    return;
+  }
+
+  m_weakPtrFactory.revokeAll();
+
+  m_webTaskRunner = taskRunner->clone();
+
+  double now = timerMonotonicallyIncreasingTime();
+  double nextFireTime = m_nextFireTime;
+  m_nextFireTime = 0;
+
+  setNextFireTime(now, nextFireTime - now);
+}
+
 // static
 WebTaskRunner* TimerBase::getTimerTaskRunner() {
   return Platform::current()->currentThread()->scheduler()->timerTaskRunner();
 }
 
 // static
 WebTaskRunner* TimerBase::getUnthrottledTaskRunner() {
   return Platform::current()->currentThread()->getWebTaskRunner();
 }
 
@@ skipping 55 matching lines @@
                                        const TimerBase* b) const {
   return a->m_nextFireTime < b->m_nextFireTime;
 }
 
 // static
 double TimerBase::timerMonotonicallyIncreasingTime() const {
   return timerTaskRunner()->monotonicallyIncreasingVirtualTimeSeconds();
 }
 
 }  // namespace blink