Media Remoting: Add RemotingController.

media/media_options.gni

 # 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/features.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 
 declare_args() {
   # Allows distributions to link pulseaudio directly (DT_NEEDED) instead of
@@ skipping 101 matching lines @@
         "cdm",
         "renderer",
       ]
       mojo_media_host = "browser"
     } else {
       mojo_media_services = [ "video_decoder" ]
       mojo_media_host = "gpu"
     }
   }
 }
+
+declare_args() {
+  # This switch defines whether the Media Remoting implementation will be built.
+  # When enabled, media is allowed to be renderer and played back on remote
+  # devices when the tab is being casted and other conditions are met.
+  enable_media_remoting = !is_chromecast && !is_ios && !is_android
+}