Decouple IPC::MessageFilter from IPC::Channel

content/browser/renderer_host/render_process_host_impl.h

Index: content/browser/renderer_host/render_process_host_impl.h
diff --git a/content/browser/renderer_host/render_process_host_impl.h b/content/browser/renderer_host/render_process_host_impl.h
index cd7ec890fdd2e2490ac686918a6a51b0e3727693..cbd2d666d1e33c9331671e9aba8bf178552628b1 100644
--- a/content/browser/renderer_host/render_process_host_impl.h
+++ b/content/browser/renderer_host/render_process_host_impl.h
@@ -43,6 +43,7 @@ struct GpuMemoryBufferHandle;
 namespace content {
 class AudioRendererHost;
 class BrowserDemuxerAndroid;
+class BrowserMessageFilterPeer;
 class GpuMessageFilter;
 class MessagePortMessageFilter;
 class MojoApplicationHost;
@@ -361,6 +362,9 @@ class CONTENT_EXPORT RenderProcessHostImpl
   // IO thread.
   scoped_refptr<RenderWidgetHelper> widget_helper_;
 
+  // Passed to added browser filters
+  scoped_ptr<BrowserMessageFilterPeer> filter_peer_;
+
   // The filter for GPU-related messages coming from the renderer.
   // Thread safety note: this field is to be accessed from the UI thread.
   // We don't keep a reference to it, to avoid it being destroyed on the UI