Move DisplayManager and DisplayChangeObserverX11 from aura to ash.

ash/extended_desktop_unittest.cc

Index: ash/extended_desktop_unittest.cc
diff --git a/ash/extended_desktop_unittest.cc b/ash/extended_desktop_unittest.cc
index b6cde7304d3df0f548b64602c3d4a0b13499bf3e..741287b7c38fffbda334b8233af3e7fb2b72eae5 100644
--- a/ash/extended_desktop_unittest.cc
+++ b/ash/extended_desktop_unittest.cc
@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 #include "ash/display/display_controller.h"
-#include "ash/display/multi_display_manager.h"
+#include "ash/display/display_manager.h"
 #include "ash/screen_ash.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
@@ -17,7 +17,6 @@
 #include "base/string_util.h"
 #include "ui/aura/client/activation_client.h"
 #include "ui/aura/client/capture_client.h"
-#include "ui/aura/env.h"
 #include "ui/aura/focus_manager.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/test/event_generator.h"
@@ -76,9 +75,8 @@ class ModalWidgetDelegate : public views::WidgetDelegateView {
   DISALLOW_COPY_AND_ASSIGN(ModalWidgetDelegate);
 };
 
-internal::MultiDisplayManager* GetDisplayManager() {
-  return static_cast<internal::MultiDisplayManager*>(
-      aura::Env::GetInstance()->display_manager());
+internal::DisplayManager* GetDisplayManager() {
+  return Shell::GetInstance()->display_manager();
 }
 
 // An event filter which moves the target window to the secondary root window