Remove some content_child dependency from content_common

content/common/gpu/gpu_channel_manager.h

Index: content/common/gpu/gpu_channel_manager.h
diff --git a/content/common/gpu/gpu_channel_manager.h b/content/common/gpu/gpu_channel_manager.h
index eb4d224d9b70f6c98e4315cbdba62b6d42c5a6a0..638028eb0bf219a7c94d49659e1d784dbc86f2f1 100644
--- a/content/common/gpu/gpu_channel_manager.h
+++ b/content/common/gpu/gpu_channel_manager.h
@@ -44,25 +44,18 @@ struct ChannelHandle;
 struct GPUCreateCommandBufferConfig;
 
 namespace content {
-class ChildThread;
 class GpuChannel;
 class GpuWatchdog;
+class MessageRouter;
 class SyncPointManager;
 
 // A GpuChannelManager is a thread responsible for issuing rendering commands
 // managing the lifetimes of GPU channels and forwarding IPC requests from the
 // browser process to them based on the corresponding renderer ID.
-//
-// A GpuChannelManager can also be hosted in the browser process in single
-// process or in-process GPU modes. In this case there is no corresponding
-// GpuChildThread and this is the reason the GpuChildThread is referenced via
-// a pointer to IPC::Sender, which can be implemented by other hosts to send
-// IPC messages to the browser process IO thread on the GpuChannelManager's
-// behalf.
 class GpuChannelManager : public IPC::Listener,
                           public IPC::Sender {
  public:
-  GpuChannelManager(ChildThread* gpu_child_thread,
+  GpuChannelManager(MessageRouter* router,
                     GpuWatchdog* watchdog,
                     base::MessageLoopProxy* io_message_loop,
                     base::WaitableEvent* shutdown_event);
@@ -138,7 +131,7 @@ class GpuChannelManager : public IPC::Listener,
   base::WaitableEvent* shutdown_event_;
 
   // Used to send and receive IPC messages from the browser process.
-  ChildThread* gpu_child_thread_;
+  MessageRouter* const router_;
 
   // These objects manage channels to individual renderer processes there is
   // one channel for each renderer process that has connected to this GPU