aura: Fix unit_tests on linux

base/message_pump_x.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/message_pump_x.h"
 
 #include <X11/extensions/XInput2.h>
 
 #include "base/basictypes.h"
 #include "base/message_loop.h"
@@ skipping 165 matching lines @@
     XEvent xev;
     XNextEvent(display, &xev);
     if (ProcessXEvent(dispatcher, &xev))
       return true;
   }
 
   return g_main_context_iteration(context, block);
 }
 
 bool MessagePumpX::WillProcessXEvent(XEvent* xevent) {
+  if (!observers().might_have_observers())
+    return false;
   ObserverListBase<MessagePumpObserver>::Iterator it(observers());
   MessagePumpObserver* obs;
   while ((obs = it.GetNext()) != NULL) {
     if (obs->WillProcessEvent(xevent))
       return true;
   }
   return false;
 }
 
 void MessagePumpX::DidProcessXEvent(XEvent* xevent) {
-  ObserverListBase<MessagePumpObserver>::Iterator it(observers());
-  MessagePumpObserver* obs;
-  while ((obs = it.GetNext()) != NULL) {
-    obs->DidProcessEvent(xevent);
-  }
+  FOR_EACH_OBSERVER(MessagePumpObserver, observers(), DidProcessEvent(xevent));
 }
 
 }  // namespace base