UserGestureIndicator: remove many unnecessary calls to isMainThread

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

Index: third_party/WebKit/Source/core/frame/DOMTimer.cpp
diff --git a/third_party/WebKit/Source/core/frame/DOMTimer.cpp b/third_party/WebKit/Source/core/frame/DOMTimer.cpp
index a6140804ca9f54ac1a5eb73cb73cc82aa0a5ac0c..5dd767478644789ffeb7c2e77d4584c527ae4750 100644
--- a/third_party/WebKit/Source/core/frame/DOMTimer.cpp
+++ b/third_party/WebKit/Source/core/frame/DOMTimer.cpp
@@ -47,7 +47,7 @@ static const double oneMillisecond = 0.001;
 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.
@@ -91,7 +91,7 @@ DOMTimer::DOMTimer(ExecutionContext* context,
       m_action(action) {
   ASSERT(timeoutID > 0);
   if (shouldForwardUserGesture(interval, m_nestingLevel))
-    m_userGestureToken = UserGestureIndicator::currentToken();
+    m_userGestureToken = UserGestureIndicator::currentTokenThreadSafe();

[kinuko, 2016/12/12 15:37:49]

Looks like we only take this code path if shouldForwardUserGesture returns true,
that never happens if we're on non-main-thread because shouldForwardUserGesture
calls processingUserGestureThreadSafe().  Is my reading right?

[Charlie Harrison, 2016/12/12 15:44:39]

Yes you're right. Let's move this one to assume we're on the main thread. I also
added a brief comment.

 
   InspectorInstrumentation::asyncTaskScheduled(
       context, singleShot ? "setTimeout" : "setInterval", this, !singleShot);