Revert of Create a unified UIElement interface for Widget, View and Window.

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 67 matching lines @@
     "debug.cc",
     "debug.h",
     "default_accessibility_delegate.cc",
     "default_accessibility_delegate.h",
     "default_wallpaper_delegate.cc",
     "default_wallpaper_delegate.h",
     "devtools/ash_devtools_css_agent.cc",
     "devtools/ash_devtools_css_agent.h",
     "devtools/ash_devtools_dom_agent.cc",
     "devtools/ash_devtools_dom_agent.h",
-    "devtools/ui_element.cc",
-    "devtools/ui_element.h",
-    "devtools/ui_element_delegate.h",
-    "devtools/view_element.cc",
-    "devtools/view_element.h",
-    "devtools/widget_element.cc",
-    "devtools/widget_element.h",
-    "devtools/window_element.cc",
-    "devtools/window_element.h",
     "display/cursor_window_controller.cc",
     "display/cursor_window_controller.h",
     "display/display_animator.h",
     "display/display_animator_chromeos.cc",
     "display/display_animator_chromeos.h",
     "display/display_color_manager_chromeos.cc",
     "display/display_color_manager_chromeos.h",
     "display/display_configuration_controller.cc",
     "display/display_configuration_controller.h",
     "display/display_error_observer_chromeos.cc",
@@ skipping 1391 matching lines @@
     "//content/public/app:both",
     "//device/bluetooth",
   ]
 
   data_deps = [
     "//ash/strings:ash_test_strings",
     "//ash/resources:ash_test_resources_with_content_100_percent",
     "//ash/resources:ash_test_resources_200_percent",
   ]
 }