Relocate display_manager from ash to ui

ash/display/mirror_window_controller.h

Index: ash/display/mirror_window_controller.h
diff --git a/ash/display/mirror_window_controller.h b/ash/display/mirror_window_controller.h
index 55a34f6aaed8cb5d5ea332e3f3c730f90d83f1ee..91ad7545a4b3fafff9754cfe4780e68200d0d6b8 100644
--- a/ash/display/mirror_window_controller.h
+++ b/ash/display/mirror_window_controller.h
@@ -12,12 +12,12 @@
 #include <vector>
 
 #include "ash/ash_export.h"
-#include "ash/display/display_manager.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host_observer.h"
+#include "ui/display/manager/display_manager.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/native_widget_types.h"
 
@@ -97,7 +97,7 @@ class ASH_EXPORT MirrorWindowController : public aura::WindowTreeHostObserver {
   typedef std::map<int64_t, MirroringHostInfo*> MirroringHostInfoMap;
   MirroringHostInfoMap mirroring_host_info_map_;
 
-  DisplayManager::MultiDisplayMode multi_display_mode_;
+  display::DisplayManager::MultiDisplayMode multi_display_mode_;
 
   std::unique_ptr<aura::client::ScreenPositionClient> screen_position_client_;