Reinstall the hotword shared module on a lanuage change.

chrome/browser/search/hotword_service.h

Index: chrome/browser/search/hotword_service.h
diff --git a/chrome/browser/search/hotword_service.h b/chrome/browser/search/hotword_service.h
index d856c099036787ce4398938adb70bce6ff18c985..b2b2188c9e1505725c9fbed6f158bc5d86e266bb 100644
--- a/chrome/browser/search/hotword_service.h
+++ b/chrome/browser/search/hotword_service.h
@@ -126,6 +126,9 @@ class HotwordService : public content::NotificationObserver,
   virtual LaunchMode GetHotwordAudioVerificationLaunchMode();
 
  private:
+  // Returns the ID of the extension that may need to be reinstalled.
+  std::string ReinstalledExtensionId();
+
   Profile* profile_;
 
   PrefChangeRegistrar pref_registrar_;