Added GPU process "echo" IPC message.

content/common/gpu/gpu_channel.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.
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
 #include "content/common/gpu/gpu_channel.h"
 
@@ skipping 242 matching lines @@
     IPC_MESSAGE_HANDLER(GpuChannelMsg_Initialize, OnInitialize)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(GpuChannelMsg_CreateOffscreenCommandBuffer,
                                     OnCreateOffscreenCommandBuffer)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(GpuChannelMsg_DestroyCommandBuffer,
                                     OnDestroyCommandBuffer)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(GpuChannelMsg_CreateOffscreenSurface,
                                     OnCreateOffscreenSurface)
     IPC_MESSAGE_HANDLER(GpuChannelMsg_DestroySurface, OnDestroySurface)
     IPC_MESSAGE_HANDLER(GpuChannelMsg_CreateTransportTexture,
         OnCreateTransportTexture)
+    IPC_MESSAGE_HANDLER(GpuChannelMsg_Echo, OnEcho);
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   DCHECK(handled) << msg.type();
   return handled;
 }
 
 void GpuChannel::HandleDeferredMessages() {
   // Empty the deferred queue so OnMessageRecieved does not defer on that
   // account and to prevent an infinite loop if the scheduler is unscheduled
   // as a result of handling already deferred messages.
@@ skipping 131 matching lines @@
                             host_id, route_id));
    router_.AddRoute(route_id, transport.get());
    transport_textures_.AddWithID(transport.release(), route_id);
 
    IPC::Message* msg = new GpuTransportTextureHostMsg_TransportTextureCreated(
        host_id, route_id);
    Send(msg);
  #endif
 }
 
+void GpuChannel::OnEcho(const IPC::Message& message) {
+  TRACE_EVENT0("gpu", "GpuCommandBufferStub::OnEcho");
+  Send(new IPC::Message(message));
+}
+
 bool GpuChannel::Init(base::MessageLoopProxy* io_message_loop,
                       base::WaitableEvent* shutdown_event) {
   // Check whether we're already initialized.
   if (channel_.get())
     return true;
 
   // Map renderer ID to a (single) channel to that process.
   std::string channel_name = GetChannelName();
   channel_.reset(new IPC::SyncChannel(
       channel_name,
@@ skipping 12 matching lines @@
 
 #if defined(OS_POSIX)
 int GpuChannel::GetRendererFileDescriptor() {
   int fd = -1;
   if (channel_.get()) {
     fd = channel_->GetClientFileDescriptor();
   }
   return fd;
 }
 #endif  // defined(OS_POSIX)