Send compositor frame IPC with metadata.

cc/gl_frame_data.h

+// Copyright 2012 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 CC_GL_FRAME_DATA_H_
+#define CC_GL_FRAME_DATA_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "cc/cc_export.h"
+
+namespace cc {
+
+class CC_EXPORT GLFrameData {
+ public:
+  GLFrameData();
+  ~GLFrameData();
+
+  std::string mailbox_name;

[piman, 2012/12/15 01:10:36]

nit: do you want to use cc::Mailbox here? The advantage is that the size is
checked in IPCs. I was going to mention that we may need to check it
somewhere...

+  uint32 sync_point;
+};
+
+}  // namespace cc
+
+#endif  // CC_GL_FRAME_DATA_H_