[Media Router] Conditionally enable mDNS on Windows.

chrome/browser/media/router/media_router.gypi

 # Copyright (c) 2015 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.
 
 # TODO(crbug.com/596999): Move non-Android code to mojo/
 {
   'variables': {
     # File lists shared with GN build.
     'media_router_sources': [
       'create_presentation_connection_request.cc',
@@ skipping 37 matching lines @@
       'route_request_result.cc',
       'route_request_result.h',
     ],
     # Files that are only needed on desktop builds
     'media_router_non_android_sources': [
       'media_router_mojo_impl.cc',
       'media_router_mojo_impl.h',
       'media_router_type_converters.cc',
       'media_router_type_converters.h',
     ],
+    'media_router_win_sources': [

[mark a. foltz, 2016/03/25 23:14:16]

This shouldn't be necessary.  The build system will filter out these files for
non-Windows builds.

[btolsch, 2016/03/26 10:53:58]

Ok, conflicting advice. I moved these back to media_router_non_android_sources.

+      'media_route_provider_util_win.cc',
+      'media_route_provider_util_win.h',
+    ],
     'media_router_test_support_sources': [
       'mock_media_router.cc',
       'mock_media_router.h',
       'mock_screen_availability_listener.cc',
       'mock_screen_availability_listener.h',
       'test_helper.cc',
       'test_helper.h',
     ],
     'media_router_non_android_test_support_sources': [
       'media_router_mojo_test.cc',
       'media_router_mojo_test.h',
     ],
   },
 }