Move Screen, its impls, DisplayObserver and DisplayChangeNotifier to ui/display

ui/display/screen_aura.cc

Index: ui/display/screen_aura.cc
diff --git a/ui/gfx/screen_aura.cc b/ui/display/screen_aura.cc
similarity index 81%
rename from ui/gfx/screen_aura.cc
rename to ui/display/screen_aura.cc
index 7a1effa0e8cef6d6c2446727089443ea77689768..a12d9a6de49ec3cddedc22a671aebf4e9c3b60fb 100644
--- a/ui/gfx/screen_aura.cc
+++ b/ui/display/screen_aura.cc
@@ -2,15 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "ui/gfx/screen.h"
+#include "ui/display/screen.h"
 
 #include "base/logging.h"
 
-namespace gfx {
+namespace display {
 
 Screen* CreateNativeScreen() {
   NOTREACHED() << "Implementation should be installed at higher level.";
   return NULL;
 }
 
-}  // namespace gfx
+}  // namespace display