Make a fairer combined message loop

base/message_loop/message_pump.h

Index: base/message_loop/message_pump.h
diff --git a/base/message_loop/message_pump.h b/base/message_loop/message_pump.h
index 5b722321495240db85ba80a943a1b7b0efe5c332..a553585c89a40ef2730a7c4933c80839dfa5af29 100644
--- a/base/message_loop/message_pump.h
+++ b/base/message_loop/message_pump.h
@@ -119,6 +119,12 @@ class BASE_EXPORT MessagePump : public RefCountedThreadSafe<MessagePump> {
   // used on the thread that called Run.
   virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) = 0;
 
+  // Returns true if the pump needs ScheduleWork to be called every time
+  // a task has been added to the incoming queue.
+  // The value return by this function should be constant over the lifetime
+  // of this, and the function could be called from any thread.
+  virtual bool NeedsScheduleWorkPerTask();
+
  protected:
   virtual ~MessagePump();
   friend class RefCountedThreadSafe<MessagePump>;