Add gpu::MailboxHolder to hold state for a gpu::Mailbox

gpu/command_buffer/common/mailbox_holder.h

Index: gpu/command_buffer/common/mailbox_holder.h
diff --git a/gpu/command_buffer/common/mailbox_holder.h b/gpu/command_buffer/common/mailbox_holder.h
new file mode 100644
index 0000000000000000000000000000000000000000..cf8f2197545516bcb6593a537003adb1597737f7
--- /dev/null
+++ b/gpu/command_buffer/common/mailbox_holder.h
@@ -0,0 +1,28 @@
+// 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 GPU_COMMAND_BUFFER_MAILBOX_HOLDER_H_
+#define GPU_COMMAND_BUFFER_MAILBOX_HOLDER_H_
+
+#include <string.h>
+
+#include "gpu/command_buffer/common/mailbox.h"
+#include "gpu/command_buffer/common/types.h"
+#include "gpu/gpu_export.h"
+
+namespace gpu {
+
+struct GPU_EXPORT MailboxHolder {
+  MailboxHolder();
+  MailboxHolder(const gpu::Mailbox& mailbox,
+                uint32 texture_target,
+                uint32 sync_point);
+  gpu::Mailbox mailbox;
+  uint32 texture_target;
+  uint32 sync_point;
+};
+
+}  // namespace gpu
+
+#endif  // GPU_COMMAND_BUFFER_MAILBOX_HOLDER_H_