Change mojo enums to be scoped enums in the generated C++ bindings.

components/mus/ws/window_tree_host_connection.cc

Index: components/mus/ws/window_tree_host_connection.cc
diff --git a/components/mus/ws/window_tree_host_connection.cc b/components/mus/ws/window_tree_host_connection.cc
index 31691034ebb3390069f9ae78ef2103b6d088814f..656b2c858255e3605893bd325ecc49f53aadcb44 100644
--- a/components/mus/ws/window_tree_host_connection.cc
+++ b/components/mus/ws/window_tree_host_connection.cc
@@ -63,7 +63,7 @@ void WindowTreeHostConnectionImpl::OnDisplayInitialized() {
   connection_manager()->AddHost(this);
   set_window_tree(connection_manager()->EmbedAtWindow(
       window_tree_host()->root_window(),
-      mojom::WindowTree::ACCESS_POLICY_EMBED_ROOT, std::move(client_)));
+      mojom::WindowTree::kAccessPolicyEmbedRoot, std::move(client_)));
 }
 
 }  // namespace ws