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

chrome/common/extensions/api/dial.idl

 // Copyright (c) 2012 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.
 
 // Use the <code>chrome.dial</code> API to discover devices that support DIAL.
 // Protocol specification: http://www.dial-multiscreen.org/
 namespace dial {
 
   // Represents a unique device that responded to a DIAL discovery request.
   dictionary DialDevice {
 
     // A label identifying the device within this instance of the browser.
     // Not guaranteed to persist beyond browser instances.
     DOMString deviceLabel;
 
     // A URL pointing to the device description resource for the device.
     DOMString deviceDescriptionUrl;
 
     // The uPnP configuration ID reported by the device.  Corresponds to the
     // CONFIGID.UPNP.ORG header in the M-SEARCH response.
     long? configId;
   };
 
   enum DialErrorCode {
     no_listeners,
+    // Deprecated.  Use onNetworkIdChanged instead.
     no_valid_network_interfaces,
+    // Deprecated.  Use onNetworkIdChanged instead.
     network_disconnected,
     cellular_network,
     socket_error,
     unknown
   };
 
   dictionary DialError {
     DialErrorCode code;
   };
 
   callback BooleanCallback = void (boolean result);
+  callback NetworkIdCallback = void (DOMString result);
 
   interface Functions {
 
     // Requests that DIAL discovery happen immediately.  The request may not be
     // honored as discovery may already be happening in the background.  The
     // callback is invoked with |true| if discovery was initiated or |false|
     // otherwise.
     static void discoverNow(BooleanCallback callback);
+
+    // Returns the current discovery network identifier.  See the documentation
+    // for onNetworkIdChanged for details.
+    static void getNetworkId(NetworkIdCallback callback);
   };
 
   interface Events {
 
     // Event fired to inform clients of the current, complete set of responsive
     // devices.  Clients should only need to store the list from the most recent
     // event.  May be fired in response to multiple circumstances:
     //
     // (1) The DIAL service refreshed its device list through periodic polling.
     // (2) A client invoked discoverNow().
     // (3) An event happened that should invalidate the device list
     //     (e.g., a network interface went offline), in which case it is fired
     //     with an empty array.
     static void onDeviceList(DialDevice[] result);
 
     // Event fired to inform clients on errors during device discovery.
     static void onError(DialError error);
+
+    // Fired when the network being used for discovery has changed.  |networkId|
+    // contains a short signature combining information from network interface
+    // and WiFi network identifiers to identify the current set of networks
+    // being used for discovery.  This can be used by clients to clear and
+    // re-bootstrap device caches on a network change.
+    //
+    // |networkId| can take the following values:
+    // - "#XXXXXX" is a signature of the set of active networks.
+    // - "disconnected" means there is no active network for discovery.
+    // - "unknown" means there is an active network, but its signature
+    //   cannot be determined.
+    //
+    // This event may be throttled to prevent it from firing too frequently; it
+    // is designed to be event-page friendly.
+    static void onNetworkIdChanged(DOMString networkId);
   };
 };