Remove usage of FOR_EACH_OBSERVER macro in services/

services/ui/ws/window_manager_window_tree_factory_set.cc

Index: services/ui/ws/window_manager_window_tree_factory_set.cc
diff --git a/services/ui/ws/window_manager_window_tree_factory_set.cc b/services/ui/ws/window_manager_window_tree_factory_set.cc
index 9c8ba110434ee74594406713491e5fe5b16e9c84..50e7822790fe3054272cc42ee8027a312fbe10dc 100644
--- a/services/ui/ws/window_manager_window_tree_factory_set.cc
+++ b/services/ui/ws/window_manager_window_tree_factory_set.cc
@@ -82,8 +82,8 @@ void WindowManagerWindowTreeFactorySet::OnWindowManagerWindowTreeFactoryReady(
     WindowManagerWindowTreeFactory* factory) {
   const bool is_first_valid_factory = !got_valid_factory_;
   got_valid_factory_ = true;
-  FOR_EACH_OBSERVER(WindowManagerWindowTreeFactorySetObserver, observers_,
-                    OnWindowManagerWindowTreeFactoryReady(factory));
+  for (auto& observer : observers_)
+    observer.OnWindowManagerWindowTreeFactoryReady(factory);
 
   // Notify after other observers as WindowServer triggers other
   // observers being added, which will have already processed the add.