High resolution timer fix for Windows

base/message_loop/message_loop.h

Index: base/message_loop/message_loop.h
diff --git a/base/message_loop/message_loop.h b/base/message_loop/message_loop.h
index 330bde6d2e8da68dccf0c1af1fcfaf2a8d081138..f6d99bf5317e1bb23267ab7f819ba28fd55a46a4 100644
--- a/base/message_loop/message_loop.h
+++ b/base/message_loop/message_loop.h
@@ -371,10 +371,6 @@ class BASE_EXPORT MessageLoop : public MessagePump::Delegate {
   void AddTaskObserver(TaskObserver* task_observer);
   void RemoveTaskObserver(TaskObserver* task_observer);
 
-  // When we go into high resolution timer mode, we will stay in hi-res mode
-  // for at least 1s.
-  static const int kHighResolutionTimerModeLeaseTimeMs = 1000;
-
 #if defined(OS_WIN)
   void set_os_modal_loop(bool os_modal_loop) {
     os_modal_loop_ = os_modal_loop;
@@ -390,7 +386,7 @@ class BASE_EXPORT MessageLoop : public MessagePump::Delegate {
 
   // Returns true if the message loop has high resolution timers enabled.
   // Provided for testing.
-  bool IsHighResolutionTimerEnabledForTesting();
+  bool HasHighResolutionTasks();
 
   // Returns true if the message loop is "idle". Provided for testing.
   bool IsIdleForTesting();
@@ -453,6 +449,7 @@ class BASE_EXPORT MessageLoop : public MessagePump::Delegate {
   virtual bool DoWork() OVERRIDE;
   virtual bool DoDelayedWork(TimeTicks* next_delayed_work_time) OVERRIDE;
   virtual bool DoIdleWork() OVERRIDE;
+  virtual void UpdateTimerGranularity() OVERRIDE;
 
   const Type type_;
 
@@ -460,6 +457,11 @@ class BASE_EXPORT MessageLoop : public MessagePump::Delegate {
   // this queue is only accessed (push/pop) by our current thread.
   TaskQueue work_queue_;
 
+  // How many high resolution tasks are in the pending task queue. This value
+  // increases by N every time we call ReloadWorkQueue() and decreases by 1
+  // every time we call RunTask() if the task needs a high resolution timer.
+  int pending_high_res_tasks_;
+
   // Contains delayed tasks, sorted by their 'delayed_run_time' property.
   DelayedTaskQueue delayed_work_queue_;