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

components/html_viewer/web_layer_tree_view_impl.cc

Index: components/html_viewer/web_layer_tree_view_impl.cc
diff --git a/components/html_viewer/web_layer_tree_view_impl.cc b/components/html_viewer/web_layer_tree_view_impl.cc
index 90e8103a6c0812537f13d0022913b0a28b2a48b8..72e298550bba636753e4b372c59c097f663085bb 100644
--- a/components/html_viewer/web_layer_tree_view_impl.cc
+++ b/components/html_viewer/web_layer_tree_view_impl.cc
@@ -76,7 +76,7 @@ void WebLayerTreeViewImpl::Initialize(mus::mojom::GpuPtr gpu_service,
         new mus::ContextProvider(cb.PassInterface().PassHandle()));
     output_surface_.reset(new mus::OutputSurface(
         context_provider,
-        window_->RequestSurface(mus::mojom::SURFACE_TYPE_DEFAULT)));
+        window_->RequestSurface(mus::mojom::SurfaceType::DEFAULT)));
   }
   layer_tree_host_->SetVisible(window_->visible());
 }