Move DisplayManager and DisplayChangeObserverX11 from aura to ash.

ui/gfx/display_observer.cc

Index: ui/gfx/display_observer.cc
diff --git a/ui/aura/display_observer.cc b/ui/gfx/display_observer.cc
similarity index 73%
rename from ui/aura/display_observer.cc
rename to ui/gfx/display_observer.cc
index d9120fdebf2fd503337241ef90c5dd361dac95d8..f8e3c07640164e35c05b76337238ab49eecb59cd 100644
--- a/ui/aura/display_observer.cc
+++ b/ui/gfx/display_observer.cc
@@ -2,11 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "ui/aura/display_observer.h"
+#include "ui/gfx/display_observer.h"
 
-namespace aura {
+namespace gfx {
 
 DisplayObserver::~DisplayObserver() {
 }
 
-}  // namespace aura
+}  // namespace gfx