Ensure that the wake up timer set by the UI worker thread in the UI message pump on Windows is set …

base/message_loop/message_pump_win.cc

Index: base/message_loop/message_pump_win.cc
diff --git a/base/message_loop/message_pump_win.cc b/base/message_loop/message_pump_win.cc
index a84e04e93a5ef90d1b03fce2afd0545f897333b7..273efdafdf89fe63ae47060374738dc24e91202f 100644
--- a/base/message_loop/message_pump_win.cc
+++ b/base/message_loop/message_pump_win.cc
@@ -93,7 +93,8 @@ int MessagePumpWin::GetCurrentDelay() const {
 // MessagePumpForUI public:
 
 MessagePumpForUI::MessagePumpForUI()
-    : atom_(0) {
+    : atom_(0),
+      force_fallback_timer_for_tasks_(0) {
   InitMessageWnd();
 
   ui_worker_thread_timer_.Set(::CreateWaitableTimer(NULL, FALSE, NULL));
@@ -125,6 +126,8 @@ void MessagePumpForUI::ScheduleWork() {
     PostWorkMessage();
     return;
   }
+
+  ::InterlockedExchange(&force_fallback_timer_for_tasks_, 1);
   // Set a one shot timer to fire after 3 milliseconds. The actual resolution
   // of the timer is dependent on timeBeginPeriod being called.
   SetWakeupTimer(kDefaultUIWorkerThreadWakeupTimerMs);
@@ -425,6 +428,7 @@ bool MessagePumpForUI::ProcessPumpReplacementMessage() {
 
 void MessagePumpForUI::DoWorkerThreadRunLoop() {
   DCHECK(ui_worker_thread_timer_.Get());
+
   while (TRUE) {
     DWORD ret = WaitForSingleObjectEx(
         ui_worker_thread_timer_.Get(), INFINITE, TRUE);
@@ -438,7 +442,8 @@ void MessagePumpForUI::DoWorkerThreadRunLoop() {
     // Set a one shot timer to process pending delayed tasks if any in the
     // queue. The actual resolution of the timer is dependent on the
     // timeBeginPeriod API being called.

[brucedawson, 2015/06/19 21:09:01]

"is dependent on the current global timer precision and therefore depends on
whether Chrome or any other process has raised the timer frequency with
timeBeginPeriod."

[ananta, 2015/06/19 22:19:10]

Done.

-    SetWakeupTimer(kDefaultUIWorkerThreadWakeupTimerMs);
+    if (::InterlockedExchange(&force_fallback_timer_for_tasks_, 0))
+      SetWakeupTimer(kDefaultUIWorkerThreadWakeupTimerMs);
   }
 }