NOT FOR REVIEW: Adding prioritized incoming task queue to renderers

base/message_loop/message_loop.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_
 #define BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_
 
 #include <queue>
 #include <string>
 
@@ skipping 356 matching lines @@
   // Provided for testing.
   bool IsHighResolutionTimerEnabledForTesting();
 
   // Returns true if the message loop is "idle". Provided for testing.
   bool IsIdleForTesting();
 
   //----------------------------------------------------------------------------
  protected:
   scoped_ptr<MessagePump> pump_;
 
+  // Loads tasks from the incoming queue to |work_queue_| if the latter is
+  // empty.
+  virtual void ReloadWorkQueue();
+
+  virtual TaskQueue& SelectNextWorkQueue();
+
  private:
   friend class internal::IncomingTaskQueue;
   friend class RunLoop;
 
   // Configures various members for the two constructors.
   void Init();
 
   // Invokes the actual run loop using the message pump.
   void RunHandler();
 
@@ skipping 13 matching lines @@
   // Delete tasks that haven't run yet without running them.  Used in the
   // destructor to make sure all the task's destructors get called.  Returns
   // true if some work was done.
   bool DeletePendingTasks();
 
   // Creates a process-wide unique ID to represent this task in trace events.
   // This will be mangled with a Process ID hash to reduce the likelyhood of
   // colliding with MessageLoop pointers on other processes.
   uint64 GetTaskTraceID(const PendingTask& task);
 
-  // Loads tasks from the incoming queue to |work_queue_| if the latter is
-  // empty.
-  void ReloadWorkQueue();
-
   // Wakes up the message pump. Can be called on any thread. The caller is
   // responsible for synchronizing ScheduleWork() calls.
   void ScheduleWork(bool was_empty);
 
   // Start recording histogram info about events and action IF it was enabled
   // and IF the statistics recorder can accept a registration of our histogram.
   void StartHistogrammer();
 
   // Add occurrence of event to our histogram, so that we can see what is being
   // done in a specific MessageLoop instance (i.e., specific thread).
@@ skipping 206 matching lines @@
 
 // Do not add any member variables to MessageLoopForIO!  This is important b/c
 // MessageLoopForIO is often allocated via MessageLoop(TYPE_IO).  Any extra
 // data that you need should be stored on the MessageLoop's pump_ instance.
 COMPILE_ASSERT(sizeof(MessageLoop) == sizeof(MessageLoopForIO),
                MessageLoopForIO_should_not_have_extra_member_variables);
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_