Expose always-on hotword preference via hotwordPrivate API.

chrome/common/extensions/api/hotword_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.
 
 // The <code>chrome.hotwordPrivate</code> API allows extensions to access and
 // mutate the preference for enabling hotword search. It also provides
 // information on whether the hotword search is available. This API provides an
 // event interface to transmit to the extension a signal that the preference fo
 // hotword search has change.
 //
@@ skipping 12 matching lines @@
     // Whether the hotword extension is available to be enabled
     boolean available;
 
     // Whether the sound of "Ok, Google" plus a few seconds before is sent
     // back to Google.
     boolean audioLoggingEnabled;
 
     // Whether experimental hotwording functionality is enabled. Mirrors the
     // "enable-experimental-hotwording" flag.
     boolean experimentalHotwordEnabled;
+
+    // Whether always-on hotwording is enabled.
+    boolean alwaysOnEnabled;
   };
 
   // The type of the recognized hotword. Right now it only has 'search' but
   // could be expanded to other types of actions in the future.
   enum HotwordType { search };
 
   callback GenericDoneCallback = void ();
   callback StatusDetailsCallback = void(StatusDetails result);
 
   interface Functions {
@@ skipping 25 matching lines @@
     // Fired when the hotword search enabled preference is changed.
     static void onEnabledChanged();
 
     // Fired when the browser wants to start a hotword session.
     static void onHotwordSessionRequested();
 
     // Fired when the browser wants to stop the requested hotword session.
     static void onHotwordSessionStopped();
   };
 };