[Media Router] Conditionally enable mDNS on Windows.

chrome/browser/ui/webui/media_router/media_router_ui.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_ui.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 
 #include "base/guid.h"
 #include "base/i18n/string_compare.h"
 #include "base/macros.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/trace_event/trace_event.h"
+#include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/media/router/create_presentation_connection_request.h"
 #include "chrome/browser/media/router/issue.h"
 #include "chrome/browser/media/router/issues_observer.h"
 #include "chrome/browser/media/router/media_route.h"
 #include "chrome/browser/media/router/media_router.h"
 #include "chrome/browser/media/router/media_router_factory.h"
 #include "chrome/browser/media/router/media_router_metrics.h"
 #include "chrome/browser/media/router/media_router_mojo_impl.h"
 #include "chrome/browser/media/router/media_routes_observer.h"
@@ skipping 143 matching lines @@
   // Create a WebUIDataSource containing the chrome://media-router page's
   // content.
   scoped_ptr<content::WebUIDataSource> html_source(
       content::WebUIDataSource::Create(chrome::kChromeUIMediaRouterHost));
 
   content::WebContents* wc = web_ui->GetWebContents();
   DCHECK(wc);
 
   router_ =
       MediaRouterFactory::GetApiForBrowserContext(wc->GetBrowserContext());
+#if defined(OS_WIN)
+  if (!router_->is_mdns_discovery_enabled()) {
+    router_->EnableMdnsDiscovery();

[imcheng, 2016/03/24 01:17:20]

Prefer to move this to InitCommon

[btolsch, 2016/03/24 01:44:04]

Done.

+  }
+#endif
 
   // Allows UI to load extensionview.
   // TODO(haibinlu): limit object-src to current extension once crbug/514866
   // is fixed.
   html_source->OverrideContentSecurityPolicyObjectSrc("object-src *;");
 
   AddLocalizedStrings(html_source.get());
   AddMediaRouterUIResources(html_source.get());
   // Ownership of |html_source| is transferred to the BrowserContext.
   content::WebUIDataSource::Add(Profile::FromWebUI(web_ui),
@@ skipping 387 matching lines @@
         base::Time::Now() - start_time_);
     start_time_ = base::Time();
   }
 }
 
 void MediaRouterUI::UpdateMaxDialogHeight(int height) {
   handler_->UpdateMaxDialogHeight(height);
 }
 
 }  // namespace media_router