Remove usage of FOR_EACH_OBSERVER macro in ui/wm/.

ui/wm/core/transient_window_manager.cc

Index: ui/wm/core/transient_window_manager.cc
diff --git a/ui/wm/core/transient_window_manager.cc b/ui/wm/core/transient_window_manager.cc
index 876a49990bf8369615dffbc05b31fea95200fc6c..6a829ed6a87259a170aa53fdea0a20adf69690ea 100644
--- a/ui/wm/core/transient_window_manager.cc
+++ b/ui/wm/core/transient_window_manager.cc
@@ -72,8 +72,8 @@ void TransientWindowManager::AddTransientChild(Window* child) {
   if (child->parent() == window_->parent())
     RestackTransientDescendants();
 
-  FOR_EACH_OBSERVER(TransientWindowObserver, observers_,
-                    OnTransientChildAdded(window_, child));
+  for (auto& observer : observers_)
+    observer.OnTransientChildAdded(window_, child);
 }
 
 void TransientWindowManager::RemoveTransientChild(Window* child) {
@@ -91,8 +91,8 @@ void TransientWindowManager::RemoveTransientChild(Window* child) {
   if (window_->parent() == child->parent())
     RestackTransientDescendants();
 
-  FOR_EACH_OBSERVER(TransientWindowObserver, observers_,
-                    OnTransientChildRemoved(window_, child));
+  for (auto& observer : observers_)
+    observer.OnTransientChildRemoved(window_, child);
 }
 
 bool TransientWindowManager::IsStackingTransient(