Deliver IPC messages together with SwapCompositorFrame

content/renderer/gpu/frame_swap_message_queue.h

+// Copyright 2014 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 CONTENT_RENDERER_GPU_FRAME_SWAP_MESSAGE_QUEUE_H_
+#define CONTENT_RENDERER_GPU_FRAME_SWAP_MESSAGE_QUEUE_H_
+
+#include <map>
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "base/synchronization/lock.h"
+
+namespace IPC {
+class Message;
+};
+
+namespace content {
+
+class FrameSwapMessageQueue :
+    public base::RefCountedThreadSafe<FrameSwapMessageQueue> {
+ public:
+  FrameSwapMessageQueue();
+
+  // takes ownership of |msg|
+  void QueueMessage(IPC::Message* msg);
+  // takes ownership of |msg|
+  // returns false if the given frame number had already been drained.
+  bool TryQueueMessage(int source_frame_number, IPC::Message* msg);
+  void DrainMessages(int source_frame_number,
+                     std::vector<IPC::Message>* messages);
+
+ private:
+  friend class base::RefCountedThreadSafe<FrameSwapMessageQueue>;
+  ~FrameSwapMessageQueue();
+  typedef std::map<int, std::vector<IPC::Message*> > FrameQueueMap;
+
+  base::Lock lock_;
+  int highest_swapped_source_frame_number_;
+  FrameQueueMap queued_messages_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameSwapMessageQueue);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_GPU_FRAME_SWAP_MESSAGE_QUEUE_H_