Hide experimental app list Google logo and custom launcher page when search engine is not Google.

ui/app_list/app_list_model_observer.h

Index: ui/app_list/app_list_model_observer.h
diff --git a/ui/app_list/app_list_model_observer.h b/ui/app_list/app_list_model_observer.h
index 13953131bca42636814a324f133a1c972025946a..09cccc0e75531c8daf4925962e3677f114af5a5b 100644
--- a/ui/app_list/app_list_model_observer.h
+++ b/ui/app_list/app_list_model_observer.h
@@ -36,6 +36,9 @@ class APP_LIST_EXPORT AppListModelObserver {
   // Triggered when the custom launcher page enabled state is changed.
   virtual void OnCustomLauncherPageEnabledStateChanged(bool enabled) {}
 
+  // Triggered when the search engine is changed to and from Google.
+  virtual void OnSearchEngineIsGoogleChanged(bool is_google) {}
+
  protected:
   virtual ~AppListModelObserver() {}
 };