Add an SVG DM source

R=mtklein@google.com,robertphillips@google.com,stephana@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2209593004

Review-Url: https://codereview.chromium.org/2209593004
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index b05fdb0..a54ddb8 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -248,6 +248,21 @@
     Path fPath;
 };
 
+#if defined(SK_XML)
+class SVGSrc : public Src {
+public:
+    explicit SVGSrc(Path path);
+
+    Error draw(SkCanvas*) const override;
+    SkISize size() const override;
+    Name name() const override;
+
+private:
+    Path fPath;
+
+    typedef Src INHERITED;
+};
+#endif // SK_XML
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
 class MSKPSrc : public Src {