Auto hide app list on Windows when it loses focus.

ui/app_list/app_list_view_delegate.h

Index: ui/app_list/app_list_view_delegate.h
diff --git a/ui/app_list/app_list_view_delegate.h b/ui/app_list/app_list_view_delegate.h
index d7e0c82f638e881b910223d7609aebba7054700f..bea240d7651c4124779dc5ccd181f4d43479c411 100644
--- a/ui/app_list/app_list_view_delegate.h
+++ b/ui/app_list/app_list_view_delegate.h
@@ -46,6 +46,12 @@ class APP_LIST_EXPORT AppListViewDelegate {
 
   // Invoked to close app list.
   virtual void Close() = 0;
+
+  // Invoked when the app list is closing.
+  virtual void ViewClosing() = 0;
+
+  // Invoked when the app list's activated state changes.
+  virtual void ViewActivationChanged(bool active) = 0;
 };
 
 }  // namespace app_list