DM: PDFSink sets rasterizer keyword

dm/DMSrcSink.h

Index: dm/DMSrcSink.h
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index 9e0ef496511b0adb336a19a27658d90f4299185d..d8811378962a706070d4695034dcd96b5d67b6bc 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -213,12 +213,14 @@ private:
 
 class PDFSink : public Sink {
 public:
-    PDFSink();
+    PDFSink(const char* rasterizer);
 
     Error draw(const Src&, SkBitmap*, SkWStream*, SkString*) const override;
     int enclave() const override { return kAnyThread_Enclave; }
     const char* fileExtension() const override { return "pdf"; }
     SinkFlags flags() const override { return SinkFlags{ SinkFlags::kVector, SinkFlags::kDirect }; }
+private:
+    const char* fRasterizer;
 };
 
 class XPSSink : public Sink {