wayland: use message_pump_observer common code

base/message_pump_wayland.h

Index: base/message_pump_wayland.h
diff --git a/base/message_pump_wayland.h b/base/message_pump_wayland.h
index 8734c7adf32263c7f3f3190a1a710397cf5b5421..706914a39b75388d75e85baf106bdef4436030d1 100644
--- a/base/message_pump_wayland.h
+++ b/base/message_pump_wayland.h
@@ -8,6 +8,7 @@
 
 #include "base/memory/scoped_ptr.h"
 #include "base/message_pump_glib.h"
+#include "base/message_pump_observer.h"
 
 typedef struct _GMainContext GMainContext;
 typedef struct _GPollFD GPollFD;
@@ -20,24 +21,6 @@ union WaylandEvent;
 }
 
 // The documentation for this class is in message_pump_glib.h
-class BASE_EXPORT MessagePumpObserver {
- public:
-   enum EventStatus {
-     EVENT_CONTINUE,    // The event should be dispatched as normal.
-     EVENT_HANDLED      // The event should not be processed any farther.
-   };
-
-  // This method is called before processing an Event. If the method returns
-  // EVENT_HANDLED, it indicates the event has already been handled, so the
-  // event is not processed any farther. If the method returns EVENT_CONTINUE,
-  // the event dispatching proceeds as normal.
-  virtual EventStatus WillProcessEvent(wayland::WaylandEvent* event);
-
- protected:
-  virtual ~MessagePumpObserver() {}
-};
-
-// The documentation for this class is in message_pump_glib.h
 //
 // The nested loop is exited by either posting a quit, or returning false
 // from Dispatch.