Remove Media Router impl and BrowserContext factory.

chrome/browser/media/router/media_router.gyp

 # Copyright 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.
 
 {
   'targets': [
     {
       'target_name': 'media_router',
       'type': 'static_library',
       'include_dirs': [
@@ skipping 12 matching lines @@
         'create_session_request.h',
         'issue.cc',
         'issue.h',
         'issue_manager.cc',
         'issue_manager.h',
         'issue_observer.h',
         'media_route.cc',
         'media_route.h',
         'media_route_id.h',
         'media_router.h',
-        'media_router_impl.cc',
-        'media_router_impl.h',
-        'media_router_impl_factory.cc',
-        'media_router_impl_factory.h',
         'media_router_type_converters.cc',
         'media_router_type_converters.h',
         'media_routes_observer.cc',
         'media_routes_observer.h',
         'media_sink.cc',
         'media_sink.h',
         'media_sinks_observer.cc',
         'media_sinks_observer.h',
         'media_source.cc',
         'media_source.h',
@@ skipping 47 matching lines @@
       'sources': [
         'mock_media_router.cc',
         'mock_media_router.h',
         'mock_screen_availability_listener.cc',
         'mock_screen_availability_listener.h',
       ],
     },
 
   ],
 }