Move IPC::MessageFilter and router to a separate file

content/common/font_cache_dispatcher_win.h

Index: content/common/font_cache_dispatcher_win.h
diff --git a/content/common/font_cache_dispatcher_win.h b/content/common/font_cache_dispatcher_win.h
index 2ae8132da6f56553140a669e738e749154a0b901..c1f4ebf1c188b8dbf131619d61e8373396c86e64 100644
--- a/content/common/font_cache_dispatcher_win.h
+++ b/content/common/font_cache_dispatcher_win.h
@@ -9,15 +9,19 @@
 
 #include "base/basictypes.h"
 #include "base/memory/singleton.h"
-#include "ipc/ipc_channel_proxy.h"
+#include "ipc/ipc_sender.h"
+#include "ipc/message_filter.h"
+
+namespace IPC {
+class Channel;
+}
 
 namespace content {
 
 // Dispatches messages used for font caching on Windows. This is needed because
 // Windows can't load fonts into its kernel cache in sandboxed processes. So the
 // sandboxed process asks the browser process to do this for it.
-class FontCacheDispatcher : public IPC::ChannelProxy::MessageFilter,
-                            public IPC::Sender {
+class FontCacheDispatcher : public IPC::MessageFilter, public IPC::Sender {
  public:
   FontCacheDispatcher();
   virtual ~FontCacheDispatcher();
@@ -26,7 +30,7 @@ class FontCacheDispatcher : public IPC::ChannelProxy::MessageFilter,
   virtual bool Send(IPC::Message* message) OVERRIDE;
 
  private:
-  // IPC::ChannelProxy::MessageFilter implementation:
+  // IPC::MessageFilter implementation:
   virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE;
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void OnChannelClosing() OVERRIDE;