SkDocument/PDF: new API

has a pdf/a switch.
sets metadata in factory.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1916093002

Review URL: https://codereview.chromium.org/1916093002
diff --git a/tests/PDFJpegEmbedTest.cpp b/tests/PDFJpegEmbedTest.cpp
index 2dcbdd0..5ef4a2d 100644
--- a/tests/PDFJpegEmbedTest.cpp
+++ b/tests/PDFJpegEmbedTest.cpp
@@ -63,7 +63,7 @@
     }
     ////////////////////////////////////////////////////////////////////////////
     SkDynamicMemoryWStream pdf;
-    SkAutoTUnref<SkDocument> document(SkDocument::CreatePDF(&pdf));
+    sk_sp<SkDocument> document(SkDocument::MakePDF(&pdf));
     SkCanvas* canvas = document->beginPage(642, 1028);
 
     canvas->clear(SK_ColorLTGRAY);
@@ -87,7 +87,7 @@
     REPORTER_ASSERT(r, !is_subset_of(cmykData.get(), pdfData.get()));
     ////////////////////////////////////////////////////////////////////////////
     pdf.reset();
-    document.reset(SkDocument::CreatePDF(&pdf));
+    document = SkDocument::MakePDF(&pdf);
     canvas = document->beginPage(642, 1028);
 
     canvas->clear(SK_ColorLTGRAY);