[SVGDom] Add <circle>, <ellipse> support

R=robertphillips@google.com,stephana@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2249033003

Review-Url: https://codereview.chromium.org/2249033003
diff --git a/BUILD.gn b/BUILD.gn
index d7dd484..8bfc984 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -521,7 +521,9 @@
     "experimental/svg/model/SkSVGAttribute.cpp",
     "experimental/svg/model/SkSVGAttributeParser.cpp",
     "experimental/svg/model/SkSVGContainer.cpp",
+    "experimental/svg/model/SkSVGCircle.cpp",
     "experimental/svg/model/SkSVGDOM.cpp",
+    "experimental/svg/model/SkSVGEllipse.cpp",
     "experimental/svg/model/SkSVGNode.cpp",
     "experimental/svg/model/SkSVGPath.cpp",
     "experimental/svg/model/SkSVGPoly.cpp",