Add DiscoveryNetworkMonitor implementation

chrome/browser/media/router/discovery/discovery_network_list.h

+// Copyright (c) 2017 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.
+
+#ifndef CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DISCOVERY_NETWORK_LIST_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DISCOVERY_NETWORK_LIST_H_
+
+#include <algorithm>
+#include <vector>
+
+#include "chrome/browser/media/router/discovery/discovery_network_info.h"
+
+// Returns a list of information about each network to which the host is
+// connected, stable-sorted by network ID (stable relative to the order they are
+// returned by the OS during enumeration).
+std::vector<DiscoveryNetworkInfo> GetDiscoveryNetworkInfoList();
+
+// Stable sort a sequence of DiscoveryNetworkInfo objects given by the iterators
+// [first, last).
+template <typename InputIt>
+void StableSortDiscoveryNetworkInfo(InputIt first, InputIt last) {
+  std::stable_sort(
+      first, last,
+      [](const DiscoveryNetworkInfo& info1, const DiscoveryNetworkInfo& info2) {
+        return info1.network_id < info2.network_id;
+      });
+}
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DISCOVERY_NETWORK_LIST_H_