ash: Change auto to not deduce raw pointers.

ash/mus/user_window_controller_impl.cc

Index: ash/mus/user_window_controller_impl.cc
diff --git a/ash/mus/user_window_controller_impl.cc b/ash/mus/user_window_controller_impl.cc
index 260811ee32884747676f09d0e7c285fc5e1c09a3..0d93eff0b55d49615dfa408d23e1114973dc0ef4 100644
--- a/ash/mus/user_window_controller_impl.cc
+++ b/ash/mus/user_window_controller_impl.cc
@@ -125,7 +125,7 @@ void UserWindowControllerImpl::AssignIdIfNecessary(::mus::Window* window) {
 void UserWindowControllerImpl::RemoveObservers(::mus::Window* user_container) {
   user_container->RemoveObserver(this);
   user_container->window_tree()->RemoveObserver(this);
-  for (auto iter : user_container->children())
+  for (auto* iter : user_container->children())
     iter->RemoveObserver(window_property_observer_.get());
 }