[chrome.dial] [WIP] Adds an API to get the active network ID.

chrome/browser/extensions/api/dial/discovery_network_monitor.h

Index: chrome/browser/extensions/api/dial/discovery_network_monitor.h
diff --git a/chrome/browser/extensions/api/dial/discovery_network_monitor.h b/chrome/browser/extensions/api/dial/discovery_network_monitor.h
new file mode 100644
index 0000000000000000000000000000000000000000..4b77b672e9056268175e918a2ab76c29bffca9d1
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+++ b/chrome/browser/extensions/api/dial/discovery_network_monitor.h
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+// Copyright (c) 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.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_DIAL_DISCOVERY_NETWORK_MONITOR_H_
+#define CHROME_BROWSER_EXTENSIONS_API_DIAL_DISCOVERY_NETWORK_MONITOR_H_
+
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "net/base/ip_address.h"
+#include "net/base/network_change_notifier.h"
+
+using net::NetworkChangeNotifier;
+
+namespace extensions {
+
+// Represents a single network interface that can be used for discovery.
+struct NetworkInfo {
+ public:
+  NetworkInfo();
+  ~NetworkInfo() = default;
+
+  // The index of the network interface.
+  uint32_t index = 0;
+  // The connection type.  Must be CONNECTION_ETHERNET or CONNECTION_WIFI.
+  NetworkChangeNotifier::ConnectionType connection_type =
+      NetworkChangeNotifier::ConnectionType::CONNECTION_UNKNOWN;
+  // The name of the network interface.
+  std::string name;
+  // A unique identifier for the network interface.
+  // For WiFi networks, this is the SSID.
+  // (TODO: How to get on Mac?)
+  // For Ethernet networks, this is the MAC address.
+  // (TODO: How to get?)
+  std::string network_id;
+  // The IP address that is currently assigned to the interface.
+  // Currently DIAL discovery is only supported over IPv4.
+  net::IPAddress ip_address;
+};
+
+// Tracks the set of active network interfaces that can be used for DIAL
+// discovery.  If the list of interfaces changes, then
+// DiscoveryNetworkMonitor::Observer is called with the instance of the manager.
+// Only one instance of this should be created per browser process.
+class DiscoveryNetworkMonitor :
+    public net::NetworkChangeNotifier::NetworkChangeObserver {
+ public:
+
+  class Observer {
+    public:
+    // Called when the list of active networks has changed.
+    virtual void OnNetworksChanged(const DiscoveryNetworkMonitor& manager) = 0;
+
+   protected:
+    ~Observer() = default;
+  };
+
+  // TODO: Implement lazy singleton constructor.
+  DiscoveryNetworkMonitor();
+  ~DiscoveryNetworkMonitor() override;
+
+  void AddObserver(Observer *const observer) {}
+  void RemoveObserver(Observer *const observer) {}
+
+  // Returns the current list of active networks.
+  const std::vector<NetworkInfo>& getNetworks() const { return networks_; }
+
+  // Computes a stable string identifier from the list of active networks.
+  // Returns "disconnected" if there are no active networks or "unknown" if the
+  // identifier could not be computed.
+  const std::string getNetworkId() const { return std::string(); }
+
+ private:
+  std::vector<NetworkInfo> networks_;
+  base::ObserverList<Observer> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(DiscoveryNetworkMonitor);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_DIAL_DISCOVERY_NETWORK_MONITOR_H_