Switch DDL rendering to be a Via in DM (take 2)

This will let us also render the GMs via DDLs.

TBR=mtklein@google.com
Change-Id: If7c2460d964822a6decc33cf5e8e685e67923127
Reviewed-on: https://skia-review.googlesource.com/116463
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index 87495a1..65c9b73 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -537,6 +537,19 @@
     std::unique_ptr<SkBBHFactory> fFactory;
 };
 
+class ViaDDL : public Via {
+public:
+    ViaDDL(int numDivisions, Sink* sink);
+    Error draw(const Src&, SkBitmap*, SkWStream*, SkString*) const override;
+private:
+#if SK_SUPPORT_GPU
+    class PromiseImageHelper;
+    class TileData;
+
+    const int fNumDivisions;
+#endif
+};
+
 class ViaSVG : public Via {
 public:
     explicit ViaSVG(Sink* sink) : Via(sink) {}