Mojo C++ bindings: switch services/ui/public/interfaces mojom target to use STL types.

services/ui/public/cpp/tests/window_tree_client_private.cc

Index: services/ui/public/cpp/tests/window_tree_client_private.cc
diff --git a/services/ui/public/cpp/tests/window_tree_client_private.cc b/services/ui/public/cpp/tests/window_tree_client_private.cc
index 77c802048f689841039408845b22ff4e6d141d81..0ab32a4966f965ff018d209aacabdd0ba1d536e6 100644
--- a/services/ui/public/cpp/tests/window_tree_client_private.cc
+++ b/services/ui/public/cpp/tests/window_tree_client_private.cc
@@ -24,7 +24,6 @@ void WindowTreeClientPrivate::OnEmbed(mojom::WindowTree* window_tree) {
   mojom::WindowDataPtr root_data(mojom::WindowData::New());
   root_data->parent_id = 0;
   root_data->window_id = next_window_id_++;
-  root_data->properties.SetToEmpty();
   root_data->visible = true;
   const int64_t display_id = 1;
   const Id focused_window_id = 0;
@@ -37,7 +36,6 @@ void WindowTreeClientPrivate::CallWmNewDisplayAdded(
   mojom::WindowDataPtr root_data(mojom::WindowData::New());
   root_data->parent_id = 0;
   root_data->window_id = next_window_id_++;
-  root_data->properties.SetToEmpty();
   root_data->visible = true;
   root_data->bounds = gfx::Rect(display.bounds().size());
   const bool parent_drawn = true;