Remove Ash shelf dimmer.

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")
 
 # Historical note: Ash shipped on Windows for a couple years to support
@@ skipping 706 matching lines @@
     "shared/immersive_context.h",
     "shared/immersive_focus_watcher.h",
     "shared/immersive_fullscreen_controller.cc",
     "shared/immersive_fullscreen_controller.h",
     "shared/immersive_fullscreen_controller_delegate.h",
     "shared/immersive_gesture_handler.h",
     "shared/immersive_handler_factory.cc",
     "shared/immersive_handler_factory.h",
     "shared/immersive_revealed_lock.cc",
     "shared/immersive_revealed_lock.h",
-    "shelf/dimmer_view.cc",
-    "shelf/dimmer_view.h",
     "shelf/shelf_bezel_event_handler.cc",
     "shelf/shelf_bezel_event_handler.h",
     "shelf/shelf_window_targeter.cc",
     "shelf/shelf_window_targeter.h",
     "shell.cc",
     "shell.h",
     "shell_init_params.h",
     "sticky_keys/sticky_keys_controller.cc",
     "sticky_keys/sticky_keys_controller.h",
     "sticky_keys/sticky_keys_overlay.cc",
@@ skipping 769 matching lines @@
   if (is_win) {
     configs -= [ "//build/config/win:console" ]
     configs += [ "//build/config/win:windowed" ]
     deps += [ "//sandbox" ]
   }
 
   if (is_chromeos) {
     deps += [ "//device/bluetooth" ]
   }
 }