Gut ash::MaterialDesignController, and remove the about:flags entry.

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 1149 matching lines @@
     "aura/pointer_watcher_adapter_unittest.cc",
     "autoclick/autoclick_unittest.cc",
     "common/devtools/ash_devtools_unittest.cc",
     "common/session/session_controller_unittest.cc",
 
     # TODO: convert to use AshTest http://crbug.com/654489.
     "common/frame/caption_buttons/frame_caption_button_container_view_unittest.cc",
     "common/frame/custom_frame_view_ash_unittest.cc",
     "common/frame/default_header_painter_unittest.cc",
 
-    # TODO: convert to use AshTest http://crbug.com/654491.
-    "common/material_design/material_design_controller_unittest.cc",
-
     # TODO: convert to use AshTest http://crbug.com/654492.
     "common/metrics/pointer_metrics_recorder_unittest.cc",
 
     # TODO: convert to use AshTest http://crbug.com/654494.
     "common/shelf/shelf_application_menu_model_unittest.cc",
     "common/shelf/shelf_background_animator_unittest.cc",
     "common/shelf/shelf_button_pressed_metric_tracker_unittest.cc",
     "common/shelf/shelf_locking_manager_unittest.cc",
     "common/shelf/shelf_model_unittest.cc",
     "common/shelf/shelf_tooltip_manager_unittest.cc",
@@ skipping 229 matching lines @@
     "//content/public/app:both",
     "//device/bluetooth",
   ]
 
   data_deps = [
     "//ash/common/strings:ash_test_strings",
     "//ash/resources:ash_test_resources_with_content_100_percent",
     "//ash/resources:ash_test_resources_200_percent",
   ]
 }