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

content/renderer/gpu/command_buffer_proxy.cc

 // Copyright (c) 2011 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.
 
 #include "content/renderer/gpu/command_buffer_proxy.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/process_util.h"
 #include "base/shared_memory.h"
@@ skipping 331 matching lines @@
     gpu::error::ContextLostReason reason) {
   // Not implemented in proxy.
   NOTREACHED();
 }
 
 void CommandBufferProxy::OnSwapBuffers() {
   if (swap_buffers_callback_.get())
     swap_buffers_callback_->Run();
 }
 
+bool CommandBufferProxy::MapExternalResource(
+    gpu::resource_type::ResourceType resource_type,
+    uint32 resource_source_id,
+    CommandBufferProxy* source_command_buffer,
+    uint32 resource_dest_id) {
+  if (last_state_.error != gpu::error::kNoError)
+    return false;
+
+  if (!Send(new GpuCommandBufferMsg_MapExternalResource(
+      route_id_,
+      resource_type,
+      resource_source_id,
+      source_command_buffer ?
+          source_command_buffer->route_id() : MSG_ROUTING_NONE,
+      resource_dest_id))) {
+    return false;
+  }
+
+  return true;
+}
+
 bool CommandBufferProxy::SetParent(CommandBufferProxy* parent_command_buffer,
                                    uint32 parent_texture_id) {
   if (last_state_.error != gpu::error::kNoError)
     return false;
 
   bool result;
   if (parent_command_buffer) {
     if (!Send(new GpuCommandBufferMsg_SetParent(
         route_id_,
         parent_command_buffer->route_id_,
@@ skipping 74 matching lines @@
   delete msg;
   return false;
 }
 
 void CommandBufferProxy::OnUpdateState(const gpu::CommandBuffer::State& state) {
   // Handle wraparound. It works as long as we don't have more than 2B state
   // updates in flight across which reordering occurs.
   if (state.generation - last_state_.generation < 0x80000000U)
     last_state_ = state;
 }