Add error handling and unit test for pdf compositor service

components/printing/service/public/cpp/pdf_compositor_client.cc

Index: components/printing/service/public/cpp/pdf_compositor_client.cc
diff --git a/components/printing/service/public/cpp/pdf_compositor_client.cc b/components/printing/service/public/cpp/pdf_compositor_client.cc
index 51aaa560bc646631d29015b5c6799b18605b9d3c..e88eb4b772f988266697e99c5526acc78be20173 100644
--- a/components/printing/service/public/cpp/pdf_compositor_client.cc
+++ b/components/printing/service/public/cpp/pdf_compositor_client.cc
@@ -19,8 +19,9 @@ void OnCompositePdf(
     printing::mojom::PdfCompositorPtr compositor,
     printing::mojom::PdfCompositor::CompositePdfCallback callback,
     scoped_refptr<base::SequencedTaskRunner> task_runner,
+    mojom::PdfCompositor::Status status,
     mojo::ScopedSharedBufferHandle pdf_handle) {
-  task_runner->PostTask(FROM_HERE, base::BindOnce(std::move(callback),
+  task_runner->PostTask(FROM_HERE, base::BindOnce(std::move(callback), status,
                                                   base::Passed(&pdf_handle)));
 }