Fine tuned availability of hotword plugin.

chrome/browser/ui/webui/app_list/start_page_handler.h

Index: chrome/browser/ui/webui/app_list/start_page_handler.h
diff --git a/chrome/browser/ui/webui/app_list/start_page_handler.h b/chrome/browser/ui/webui/app_list/start_page_handler.h
index c3d35bbd026b7ef4aeb487a85f956f07e3f6a56a..b444f752897561e1b08c68de6f4eac13bb0e2667 100644
--- a/chrome/browser/ui/webui/app_list/start_page_handler.h
+++ b/chrome/browser/ui/webui/app_list/start_page_handler.h
@@ -7,6 +7,7 @@
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/prefs/pref_change_registrar.h"
 #include "chrome/browser/ui/app_list/recommended_apps_observer.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
@@ -35,6 +36,18 @@ class StartPageHandler : public content::WebUIMessageHandler,
   // Creates a ListValue for the recommended apps and sends it to js side.
   void SendRecommendedApps();
 
+#if defined(OS_CHROMEOS)
+  // Returns true if the hotword is enabled.
+  bool HotwordEnabled();
+
+  // Called when the pref has been changed.
+  void OnHotwordEnabledChanged();
+
+  // Called when the availability of the hotword for NTP is changed. The new
+  // value has to be propagated.
+  void SynchronizeHotwordEnabled();
+#endif
+
   // JS callbacks.
   void HandleInitialize(const base::ListValue* args);
   void HandleLaunchApp(const base::ListValue* args);
@@ -43,6 +56,7 @@ class StartPageHandler : public content::WebUIMessageHandler,
   void HandleSpeechRecognition(const base::ListValue* args);
 
   RecommendedApps* recommended_apps_;  // Not owned.
+  PrefChangeRegistrar pref_change_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(StartPageHandler);
 };