reset before clearning composition order.

shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm

@@ -635,20 +635,20 @@ static bool ClipRRectContainsPlatformViewBoundingRect(const SkRRect& clip_rrect,
 }
 
 void FlutterPlatformViewsController::Reset() {
-  composition_order_.clear();
-  slices_.clear();
-  current_composition_params_.clear();
-  views_to_recomposite_.clear();
-  layer_pool_->RecycleLayers();
-  visited_platform_views_.clear();
-
   fml::TaskRunner::RunNowOrPostTask(
       platform_task_runner_, [&, composition_order = composition_order_]() {
         for (int64_t view_id : composition_order_) {
           [platform_views_[view_id].root_view.get() removeFromSuperview];
         }
         platform_views_.clear();
       });
+
+  composition_order_.clear();
+  slices_.clear();
+  current_composition_params_.clear();
+  views_to_recomposite_.clear();
+  layer_pool_->RecycleLayers();
+  visited_platform_views_.clear();
 }
 
 bool FlutterPlatformViewsController::SubmitFrame(GrDirectContext* gr_context,