Use the new hotword extension in the launcher when it is enabled.

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 21 matching lines @@
 
 // Provides an interface for the Hotword component that does voice triggered
 // search.
 class HotwordService : public content::NotificationObserver,
                        public extensions::ExtensionRegistryObserver,
                        public KeyedService {
  public:
   // Returns true if the hotword supports the current system language.
   static bool DoesHotwordSupportLanguage(Profile* profile);
 
+  // Returns true is the "enable-experimental-hotwording" flag is set.

[Matt Giuca, 2014/08/14 07:45:23]

s/is/if/

[Jun Mukai, 2014/08/14 22:10:08]

No one explains what is experimental hotwording, and how it's different from the
normal hotwording.  Please explain briefly on the switches.cc or here.

[Anand Mistry (off Chromium), 2014/08/15 00:14:51]

Added a small blurb to chrome/common/chrome_switches.cc

[Anand Mistry (off Chromium), 2014/08/15 00:14:51]

Done.

+  static bool IsExperimentalHotwordingEnabled();
+
   explicit HotwordService(Profile* profile);
   virtual ~HotwordService();
 
   // Overridden from content::NotificationObserver:
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
   // Overridden from ExtensionRegisterObserver:
   virtual void OnExtensionInstalled(
@@ skipping 68 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_