Add GetCurrentRoutes() to MediaRouter API, ensure dialog has routes at init

chrome/browser/ui/webui/media_router/media_router_webui_message_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/media_router/media_router_webui_message_handler.h"
 
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 392 matching lines @@
 
   // "No Cast devices found?" Chromecast help center page.
   initial_data.SetString("deviceMissingUrl",
       base::StringPrintf(kHelpPageUrlPrefix, 3249268));
 
   std::unique_ptr<base::DictionaryValue> sinks_and_identity(
       SinksAndIdentityToValue(media_router_ui_->sinks(), GetAccountInfo()));
   initial_data.Set("sinksAndIdentity", sinks_and_identity.release());
 
   std::unique_ptr<base::ListValue> routes(RoutesToValue(
-      media_router_ui_->routes(), media_router_ui_->joinable_route_ids(),
+      media_router_ui_->GetRoutes(), media_router_ui_->joinable_route_ids(),
       media_router_ui_->current_cast_modes()));
   initial_data.Set("routes", routes.release());
 
   const std::set<MediaCastMode> cast_modes = media_router_ui_->cast_modes();
   std::unique_ptr<base::ListValue> cast_modes_list(CastModesToValue(
       cast_modes, media_router_ui_->GetPresentationRequestSourceName()));
   initial_data.Set("castModes", cast_modes_list.release());
 
   web_ui()->CallJavascriptFunctionUnsafe(kSetInitialData, initial_data);
   media_router_ui_->UIInitialized();
@@ skipping 456 matching lines @@
   }
 
   return value;
 }
 
 void MediaRouterWebUIMessageHandler::SetWebUIForTest(content::WebUI* web_ui) {
   set_web_ui(web_ui);
 }
 
 }  // namespace media_router