add ViaSVG to dm

BUG=skia:

Change-Id: I52892a0dd466bee6e3abcaa89a373b93493d201f
Reviewed-on: https://skia-review.googlesource.com/8682
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index cac8848..f2b09f6 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -467,6 +467,12 @@
     Error draw(const Src&, SkBitmap*, SkWStream*, SkString*) const override;
 };
 
+class ViaSVG : public Via {
+public:
+    explicit ViaSVG(Sink* sink) : Via(sink) {}
+    Error draw(const Src&, SkBitmap*, SkWStream*, SkString*) const override;
+};
+
 class ViaMojo : public Via {
 public:
     explicit ViaMojo(Sink* sink) : Via(sink) {}