Adds DidProcessEvent to MessagePumpGLib.

base/message_pump_glib.h

Index: base/message_pump_glib.h
===================================================================
--- base/message_pump_glib.h	(revision 16377)
+++ base/message_pump_glib.h	(working copy)
@@ -26,6 +26,9 @@
 
     // This method is called before processing a message.
     virtual void WillProcessEvent(GdkEvent* event) = 0;
+
+    // This method is called after processing a message.
+    virtual void DidProcessEvent(GdkEvent* event) = 0;
   };
 
   MessagePumpForUI();
@@ -72,6 +75,10 @@
   // process an event.
   void WillProcessEvent(GdkEvent* event);
 
+  // Invoked from EventDispatcher. Notifies all observers we processed an
+  // event.
+  void DidProcessEvent(GdkEvent* event);
+
   // Callback prior to gdk dispatching an event.
   static void EventDispatcher(GdkEvent* event, gpointer data);