Add a RenderProcessObserver. For now this will be primarily used to filter control messages, so ...

chrome/renderer/render_thread.h

Index: chrome/renderer/render_thread.h
===================================================================
--- chrome/renderer/render_thread.h	(revision 79468)
+++ chrome/renderer/render_thread.h	(working copy)
@@ -10,6 +10,7 @@
 #include <string>
 #include <vector>
 
+#include "base/observer_list.h"
 #include "base/shared_memory.h"
 #include "base/time.h"
 #include "base/timer.h"
@@ -34,6 +35,7 @@
 class ListValue;
 class RendererHistogram;
 class RendererHistogramSnapshots;
+class RenderProcessObserver;
 class RendererNetPredictor;
 class RendererWebKitClientImpl;
 class SpellCheck;
@@ -169,6 +171,9 @@
   virtual bool IsExtensionProcess() const;
   virtual bool IsIncognitoProcess() const;
 
+  void AddObserver(RenderProcessObserver* observer);
+  void RemoveObserver(RenderProcessObserver* observer);
+
   // These methods modify how the next message is sent.  Normally, when sending
   // a synchronous message that runs a nested message loop, we need to suspend
   // callbacks into WebKit.  This involves disabling timers and deferring
@@ -413,6 +418,8 @@
 
   chrome::ChromeContentRendererClient renderer_client_;
 
+  ObserverList<RenderProcessObserver> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderThread);
 };