Initial implementation of session APIs, sans WiFi component

chrome/common/extensions/api/gcd_private.idl

 // Copyright 2014 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.gcdPrivate</code> API to discover GCD APIs and register
 // them.
 namespace gcdPrivate {
 
   enum SetupType { mdns, wifi, cloud };
 
@@ skipping 25 matching lines @@
     // populateWifiPassword was true and the message cannot be parsed as a setup
     // message.
     setupParseError,
 
     // Could not connect to the device.
     connectionError,
 
     // Error in establishing session.
     sessionError,
 
+    // Unknown session.
+    unknownSessionError,
+
     // Success.
     success
   };
 
   enum ConfirmationType {
     displayCode,
     audio
   };
 
   callback CloudDeviceListCallback = void(GCDDevice[] devices);
@@ skipping 122 matching lines @@
     // Subscribe to this event to start listening new or updated devices. New
     // listeners will get called with all known devices on the network, and
     // status updates for devices available through the cloud.
     static void onDeviceStateChanged(GCDDevice device);
 
     // Notifies that device has disappeared.
     // |deviceId| : The device has disappeared.
     static void onDeviceRemoved(DOMString deviceId);
   };
 };