Move IPC::MessageFilter and router to a separate file

chrome/renderer/media/cast_ipc_dispatcher.h

Index: chrome/renderer/media/cast_ipc_dispatcher.h
diff --git a/chrome/renderer/media/cast_ipc_dispatcher.h b/chrome/renderer/media/cast_ipc_dispatcher.h
index 4e87f2e56285321b684cfe88065c4cb7217c2ced..320b79761367dde3b790f8a99f521446d177b050 100644
--- a/chrome/renderer/media/cast_ipc_dispatcher.h
+++ b/chrome/renderer/media/cast_ipc_dispatcher.h
@@ -8,6 +8,7 @@
 #include "base/callback.h"
 #include "base/id_map.h"
 #include "ipc/ipc_channel_proxy.h"
+#include "ipc/message_filter.h"
 #include "media/cast/cast_sender.h"
 #include "media/cast/logging/logging_defines.h"
 #include "media/cast/transport/cast_transport_sender.h"
@@ -16,7 +17,7 @@ class CastTransportSenderIPC;
 
 // This dispatcher listens to incoming IPC messages and sends
 // the call to the correct CastTransportSenderIPC instance.
-class CastIPCDispatcher : public IPC::ChannelProxy::MessageFilter {
+class CastIPCDispatcher : public IPC::MessageFilter {
  public:
   explicit CastIPCDispatcher(
       const scoped_refptr<base::MessageLoopProxy>& io_message_loop);
@@ -26,7 +27,7 @@ class CastIPCDispatcher : public IPC::ChannelProxy::MessageFilter {
   int32 AddSender(CastTransportSenderIPC* sender);
   void RemoveSender(int32 channel_id);
 
-  // IPC::ChannelProxy::MessageFilter implementation
+  // IPC::MessageFilter implementation
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE;
   virtual void OnFilterRemoved() OVERRIDE;