Remove enable_media_router.

chrome/browser/ui/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/chromecast_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 3409 matching lines @@
       "webui/extensions/extension_icon_source.h",
     ]
   }
   if (enable_google_now && !is_android) {
     sources += [
       # These are non-Android because Android excludes all of options.
       "webui/options/geolocation_options_handler.cc",
       "webui/options/geolocation_options_handler.h",
     ]
   }
-  if (enable_media_router && !is_android) {
+  if (!is_android) {
     sources += [
       "toolbar/media_router_action.cc",
       "toolbar/media_router_action.h",
       "toolbar/media_router_action_controller.cc",
       "toolbar/media_router_action_controller.h",
       "toolbar/media_router_action_platform_delegate.h",
       "toolbar/media_router_contextual_menu.cc",
       "toolbar/media_router_contextual_menu.h",
       "views/toolbar/media_router_action_platform_delegate_views.cc",
       "views/toolbar/media_router_action_platform_delegate_views.h",
@@ skipping 130 matching lines @@
       "test/test_confirm_bubble_model.cc",
       "test/test_confirm_bubble_model.h",
     ]
     deps += [ "//chrome/test:test_support_ui" ]
   }
 
   if (enable_extensions) {
     deps += [ "//extensions/browser" ]
   }
 }