Remove DisplayChangeObserver ash dependencies.

ash/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//ui/base/ui_features.gni")
 
 assert(use_aura)
@@ skipping 633 matching lines @@
     "display/root_window_transformers.cc",
     "display/root_window_transformers.h",
     "display/screen_ash.cc",
     "display/screen_ash.h",
     "display/screen_orientation_controller_chromeos.cc",
     "display/screen_orientation_controller_chromeos.h",
     "display/screen_position_controller.cc",
     "display/screen_position_controller.h",
     "display/shared_display_edge_indicator.cc",
     "display/shared_display_edge_indicator.h",
+    "display/shutdown_observer_chromeos.cc",
+    "display/shutdown_observer_chromeos.h",
     "display/unified_mouse_warp_controller.cc",
     "display/unified_mouse_warp_controller.h",
     "display/window_tree_host_manager.cc",
     "display/window_tree_host_manager.h",
     "drag_drop/drag_drop_controller.cc",
     "drag_drop/drag_drop_controller.h",
     "drag_drop/drag_drop_tracker.cc",
     "drag_drop/drag_drop_tracker.h",
     "first_run/desktop_cleaner.cc",
     "first_run/desktop_cleaner.h",
@@ skipping 842 matching lines @@
   if (is_win) {
     configs -= [ "//build/config/win:console" ]
     configs += [ "//build/config/win:windowed" ]
     deps += [ "//sandbox" ]
   }
 
   if (is_chromeos) {
     deps += [ "//device/bluetooth" ]
   }
 }