[Media Router] Conditionally enable mDNS on Windows.

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

Index: chrome/browser/ui/webui/media_router/media_router_ui.cc
diff --git a/chrome/browser/ui/webui/media_router/media_router_ui.cc b/chrome/browser/ui/webui/media_router/media_router_ui.cc
index 7bf21a1e359948f7252ebb8902ab7d130caa1020..397573c77eba01fa94b40a7f2c73c61f4325af12 100644
--- a/chrome/browser/ui/webui/media_router/media_router_ui.cc
+++ b/chrome/browser/ui/webui/media_router/media_router_ui.cc
@@ -14,6 +14,7 @@
 #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"
@@ -177,6 +178,11 @@ MediaRouterUI::MediaRouterUI(content::WebUI* web_ui)
 
   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