Eagerly remove disposed DOMTimers as observers upon completion.

third_party/WebKit/Source/core/frame/DOMTimer.cpp

 /*
  * Copyright (C) 2008 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 43 matching lines @@
 int DOMTimer::install(ExecutionContext* context, ScheduledAction* action, int timeout, bool singleShot)
 {
     int timeoutID = context->timers()->installNewTimeout(context, action, timeout, singleShot);
     TRACE_EVENT_INSTANT1("devtools.timeline", "TimerInstall", TRACE_EVENT_SCOPE_THREAD, "data", InspectorTimerInstallEvent::data(context, timeoutID, timeout, singleShot));
     InspectorInstrumentation::NativeBreakpoint nativeBreakpoint(context, "setTimer", true);
     return timeoutID;
 }
 
 void DOMTimer::removeByID(ExecutionContext* context, int timeoutID)
 {
-    context->timers()->removeTimeoutByID(timeoutID);
+    DOMTimer* timer = context->timers()->removeTimeoutByID(timeoutID);
     TRACE_EVENT_INSTANT1("devtools.timeline", "TimerRemove", TRACE_EVENT_SCOPE_THREAD, "data", InspectorTimerRemoveEvent::data(context, timeoutID));
     InspectorInstrumentation::NativeBreakpoint nativeBreakpoint(context, "clearTimer", true);
+    // Eagerly unregister as ExecutionContext observer.
+    if (timer)
+        timer->clearContext();
 }
 
 DOMTimer::DOMTimer(ExecutionContext* context, ScheduledAction* action, int interval, bool singleShot, int timeoutID)
     : SuspendableTimer(context)
     , m_timeoutID(timeoutID)
     , m_nestingLevel(context->timers()->timerNestingLevel() + 1)
     , m_action(action)
 {
     ASSERT(timeoutID > 0);
     if (shouldForwardUserGesture(interval, m_nestingLevel))
@@ skipping 50 matching lines @@
     // Unregister the timer from ExecutionContext before executing the action
     // for one-shot timers.
     ScheduledAction* action = m_action.release();
     context->timers()->removeTimeoutByID(m_timeoutID);
 
     action->execute(context);
 
     TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "UpdateCounters", TRACE_EVENT_SCOPE_THREAD, "data", InspectorUpdateCountersEvent::data());
 
     // ExecutionContext might be already gone when we executed action->execute().
-    if (getExecutionContext())
-        getExecutionContext()->timers()->setTimerNestingLevel(0);
+    ExecutionContext* executionContext = getExecutionContext();
+    if (!executionContext)
+        return;
+
+    executionContext->timers()->setTimerNestingLevel(0);
+    // Eagerly unregister as ExecutionContext observer.
+    clearContext();
 }
 
 void DOMTimer::stop()
 {
     InspectorInstrumentation::asyncTaskCanceled(getExecutionContext(), this);
     SuspendableTimer::stop();
     // Need to release JS objects potentially protected by ScheduledAction
     // because they can form circular references back to the ExecutionContext
     // which will cause a memory leak.
     m_action.clear();
 }
 
 WebTaskRunner* DOMTimer::timerTaskRunner() const
 {
     return getExecutionContext()->timers()->timerTaskRunner();
 }
 
 DEFINE_TRACE(DOMTimer)
 {
     visitor->trace(m_action);
     SuspendableTimer::trace(visitor);
 }
 
 } // namespace blink