[Media Router] Conditionally enable mDNS on Windows.

chrome/browser/media/router/media_route_provider_util.cc

+// Copyright 2016 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/media/router/media_route_provider_util.h"
+
+#include "base/files/file_path.h"
+#include "base/location.h"
+#include "base/path_service.h"
+#include "build/build_config.h"
+#include "chrome/installer/util/browser_distribution.h"

[mark a. foltz, 2016/03/24 22:59:32]

Do you need to declare any additional deps= in the .gn/.gyp files for the build/
or installer/ libraries?

[btolsch, 2016/03/25 04:40:50]

I didn't think so because nothing has been failing to build/link. How can I tell
if I need to add something?

+#include "chrome/installer/util/firewall_manager_win.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace media_router {
+
+#if defined(OS_WIN)
+namespace {
+
+void DoCanFirewallUseLocalPorts(MediaRouterMojoImpl* router) {
+  base::FilePath exe_path;
+  if (base::PathService::Get(base::FILE_EXE, &exe_path)) {
+    auto firewall_manager = installer::FirewallManager::Create(
+        BrowserDistribution::GetDistribution(), exe_path);
+    if (firewall_manager && firewall_manager->CanUseLocalPorts()) {
+      content::BrowserThread::PostTask(
+          content::BrowserThread::UI, FROM_HERE,
+          base::Bind(&MediaRouterMojoImpl::EnableMdnsDiscovery,
+                     base::Unretained(router)));
+    }
+  }
+}
+
+}  // namespace
+
+void CanFirewallUseLocalPorts(MediaRouterMojoImpl* router) {
+  content::BrowserThread::PostTask(
+      content::BrowserThread::FILE, FROM_HERE,
+      base::Bind(&DoCanFirewallUseLocalPorts, router));
+}
+#endif
+
+}  // namespace media_router