fix lint error

Author: ColdPaleLight

lib/ui/painting/image_encoding_skia.cc

@@ -17,6 +17,8 @@ void ConvertImageToRasterSkia(
     const fml::WeakPtr<GrDirectContext>& resource_context,
     const fml::TaskRunnerAffineWeakPtr<SnapshotDelegate>& snapshot_delegate,
     const std::shared_ptr<const fml::SyncSwitch>& is_gpu_disabled_sync_switch) {
+  FML_DCHECK(raster_task_runner && io_task_runner);
+
   // If the owning_context is kRaster, we can't access it on this task runner.
   if (dl_image->owning_context() != DlImage::OwningContext::kRaster) {
     auto image = dl_image->skia_image();