UserGestureIndicator: remove many unnecessary calls to isMainThread

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 29 matching lines @@
 static const int maxTimerNestingLevel = 5;
 static const double oneMillisecond = 0.001;
 // Chromium uses a minimum timer interval of 4ms. We'd like to go
 // lower; however, there are poorly coded websites out there which do
 // create CPU-spinning loops.  Using 4ms prevents the CPU from
 // spinning too busily and provides a balance between CPU spinning and
 // the smallest possible interval timer.
 static const double minimumInterval = 0.004;
 
 static inline bool shouldForwardUserGesture(int interval, int nestingLevel) {
-  return UserGestureIndicator::processingUserGesture() &&
+  return UserGestureIndicator::processingUserGestureThreadSafe() &&
          interval <= maxIntervalForUserGestureForwarding &&
          nestingLevel ==
              1;  // Gestures should not be forwarded to nested timers.
 }
 
 int DOMTimer::install(ExecutionContext* context,
                       ScheduledAction* action,
                       int timeout,
                       bool singleShot) {
   int timeoutID = context->timers()->installNewTimeout(context, action, timeout,
@@ skipping 22 matching lines @@
 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))
+  if (shouldForwardUserGesture(interval, m_nestingLevel)) {
+    // Thread safe because shouldForwardUserGesture will only return true if
+    // execution is on the the main thread.
     m_userGestureToken = UserGestureIndicator::currentToken();
+  }
 
   InspectorInstrumentation::asyncTaskScheduled(
       context, singleShot ? "setTimeout" : "setInterval", this, !singleShot);
 
   double intervalMilliseconds =
       std::max(oneMillisecond, interval * oneMillisecond);
   if (intervalMilliseconds < minimumInterval &&
       m_nestingLevel >= maxTimerNestingLevel)
     intervalMilliseconds = minimumInterval;
   if (singleShot)
@@ skipping 79 matching lines @@
 WebTaskRunner* DOMTimer::timerTaskRunner() const {
   return getExecutionContext()->timers()->timerTaskRunner();
 }
 
 DEFINE_TRACE(DOMTimer) {
   visitor->trace(m_action);
   SuspendableTimer::trace(visitor);
 }
 
 }  // namespace blink