Allow the renderer process to map textures from one context into another.

content/common/gpu/gpu_command_buffer_stub.h

Index: content/common/gpu/gpu_command_buffer_stub.h
===================================================================
--- content/common/gpu/gpu_command_buffer_stub.h	(revision 94701)
+++ content/common/gpu/gpu_command_buffer_stub.h	(working copy)
@@ -16,6 +16,7 @@
 #include "base/process.h"
 #include "base/task.h"
 #include "content/common/gpu/media/gpu_video_decode_accelerator.h"
+#include "gpu/command_buffer/common/constants.h"
 #include "gpu/command_buffer/service/command_buffer_service.h"
 #include "gpu/command_buffer/service/gpu_scheduler.h"
 #include "ipc/ipc_channel.h"
@@ -91,6 +92,10 @@
   void OnInitialize(base::SharedMemoryHandle ring_buffer,
                     int32 size,
                     IPC::Message* reply_message);
+  void OnMapExternalResource(gpu::resource_type::ResourceType resource_type,
+                             uint32 resource_source_id,
+                             int32 source_route_id,
+                             uint32 resource_dest_id);
   void OnSetParent(int32 parent_route_id,
                    uint32 parent_texture_id,
                    IPC::Message* reply_message);