Add DiscoveryNetworkMonitor implementation

chrome/test/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/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//chrome/common/features.gni")
@@ skipping 4362 matching lines @@
       "//ipc",
       "//printing:test_support",
     ]
   }
 
   if (enable_media_router) {
     sources += [
       "../browser/media/cast_remoting_connector_unittest.cc",
       "../browser/media/router/browser_presentation_connection_proxy_unittest.cc",
       "../browser/media/router/create_presentation_connection_request_unittest.cc",
+      "../browser/media/router/discovery/discovery_network_list_unittest.cc",
+      "../browser/media/router/discovery/discovery_network_monitor_unittest.cc",
       "../browser/media/router/issue_manager_unittest.cc",
       "../browser/media/router/issue_unittest.cc",
       "../browser/media/router/media_route_unittest.cc",
       "../browser/media/router/media_router_base_unittest.cc",
       "../browser/media/router/media_router_dialog_controller_unittest.cc",
       "../browser/media/router/media_router_factory_unittest.cc",
       "../browser/media/router/media_router_metrics_unittest.cc",
       "../browser/media/router/media_sink_unittest.cc",
       "../browser/media/router/media_sinks_observer_unittest.cc",
       "../browser/media/router/media_source_helper_unittest.cc",
@@ skipping 110 matching lines @@
       "../tools/convert_dict/convert_dict_unittest.cc",
     ]
 
     # The test fetches resources which means Mac need the app bundle to exist
     # on disk so it can pull from it.
     deps += [
       "//third_party/google_toolbox_for_mac",
       "//third_party/ocmock",
     ]
 
-    sources += [
-      "../browser/ui/cocoa/applescript/apple_event_util_unittest.mm",
-    ]
+    sources +=
+        [ "../browser/ui/cocoa/applescript/apple_event_util_unittest.mm" ]
 
     if (mac_views_browser) {
       # TODO(tapted): Add chrome_unit_tests_views_non_mac_sources.
     } else {
       sources += [
         "../browser/ui/cocoa/accelerators_cocoa_unittest.mm",
         "../browser/ui/cocoa/animatable_image_unittest.mm",
         "../browser/ui/cocoa/animatable_view_unittest.mm",
         "../browser/ui/cocoa/app_menu/app_menu_button_cell_unittest.mm",
         "../browser/ui/cocoa/app_menu/app_menu_controller_unittest.mm",
@@ skipping 657 matching lines @@
 }
 
 if (is_win) {
   loadable_module("conflicts_dll") {
     testonly = true
     sources = [
       "conflicts/conflicts_dll.cc",
     ]
   }
 }