Fix WebGL rendering for the webdemo

PiperOrigin-RevId: 840640628
Change-Id: I4bac3bf634e66da01174927bf6096bc1df642e10

src/experimental/filament/filament/filament_context.cc

@@ -161,8 +161,10 @@ void FilamentContext::Render(const mjrRect& viewport, const mjvScene* scene,
   if (!render_to_texture_) {
     filament::View* view = scene_view_->PrepareRenderView(last_render_mode_);
 
+    #ifndef __EMSCRIPTEN__
     // Wait until previous frame is completed before requesting a new frame.
     engine_->flushAndWait();
+    #endif
 
     if (renderer_->beginFrame(swap_chain_)) {
       renderer_->render(view);

src/experimental/filament/filament/scene_view.cc

@@ -289,7 +289,10 @@ void SceneView::PrepareLights() {
         params.spot_cone_angle = model->light_cutoff[i];
       }
       auto light_obj = std::make_unique<Light>(object_mgr_, params);
+#ifndef __EMSCRIPTEN__
+      // TODO(b/458045799): Re-enable when lights work on glinux and chromebook.
       light_obj->AddToScene(scene_);
+#endif
       lights_.emplace_back(std::move(light_obj));
     }
   }