Adds a skeleton component app for Always-On Hotwording opt-in flow.

chrome/browser/search/hotword_service.h

 // Copyright 2013 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_SEARCH_HOTWORD_SERVICE_H_
 #define CHROME_BROWSER_SEARCH_HOTWORD_SERVICE_H_
 
 #include "base/basictypes.h"
 #include "base/memory/weak_ptr.h"
 #include "base/prefs/pref_change_registrar.h"
@@ skipping 58 matching lines @@
   virtual bool IsHotwordAllowed();
 
   // Checks if the user has opted into audio logging. Returns true if the user
   // is opted in, false otherwise..
   bool IsOptedIntoAudioLogging();
 
   // Control the state of the hotword extension.
   void EnableHotwordExtension(ExtensionService* extension_service);
   void DisableHotwordExtension(ExtensionService* extension_service);
 
+  // Handles launching the Hotword Audio Verification extension when the user
+  // turns it on via the settings menu.
+  void OnHotwordAlwaysOnSearchEnabledChanged(const std::string& pref_name);
+
   // Handles enabling/disabling the hotword extension when the user
   // turns it off via the settings menu.
   void OnHotwordSearchEnabledChanged(const std::string& pref_name);
 
   // Called to handle the hotword session from |client|.
   void RequestHotwordSession(HotwordClient* client);
   void StopHotwordSession(HotwordClient* client);
   HotwordClient* client() { return client_; }
 
   // Checks if the current version of the hotword extension should be
@@ skipping 34 matching lines @@
   HotwordClient* client_;
   int error_message_;
   bool reinstall_pending_;
 
   base::WeakPtrFactory<HotwordService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HotwordService);
 };
 
 #endif  // CHROME_BROWSER_SEARCH_HOTWORD_SERVICE_H_