Remove enable_media_router.

chrome/utility/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/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/sysroot.gni")
 import("//extensions/features/features.gni")
 import("//printing/features/features.gni")
 
@@ skipping 161 matching lines @@
     sources -= [
       "printing_handler.cc",
       "printing_handler.h",
     ]
   }
 
   if (is_mac && safe_browsing_mode == 1) {
     deps += [ "//chrome/utility/safe_browsing/mac" ]
   }
 
-  if (enable_media_router && !is_android) {
+  if (!is_android) {
     sources += [
       "media_router/dial_device_description_parser_impl.cc",
       "media_router/dial_device_description_parser_impl.h",
     ]
   }
 }