MediaService: Implement GetChannelToken IPC

media/gpu/ipc/service/media_channel.h

Index: media/gpu/ipc/service/media_channel.h
diff --git a/media/gpu/ipc/service/media_channel.h b/media/gpu/ipc/service/media_channel.h
index 6e7c74c90cc5670207f92563294b4cc4c6b75758..cc3d31d5d97a4d97246062813736680a59d62dd5 100644
--- a/media/gpu/ipc/service/media_channel.h
+++ b/media/gpu/ipc/service/media_channel.h
@@ -7,6 +7,7 @@
 
 #include <memory>
 
+#include "base/memory/ref_counted.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "media/gpu/ipc/service/gpu_jpeg_decode_accelerator.h"
@@ -24,6 +25,7 @@ class GpuCommandBufferStub;
 namespace media {
 
 class MediaChannelDispatchHelper;
+class MediaChannelFilter;
 
 class MediaChannel : public IPC::Listener, public IPC::Sender {
  public:
@@ -50,6 +52,7 @@ class MediaChannel : public IPC::Listener, public IPC::Sender {
                             IPC::Message* reply_message);
 
   gpu::GpuChannel* const channel_;
+  scoped_refptr<MediaChannelFilter> channel_filter_;
   std::unique_ptr<GpuJpegDecodeAccelerator> jpeg_decoder_;
   DISALLOW_COPY_AND_ASSIGN(MediaChannel);
 };