[SVGDom] Fix <ellipse> positioning

R=robertphillips@google.com,stephana@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2253283002

Review-Url: https://codereview.chromium.org/2253283002
diff --git a/experimental/svg/model/SkSVGEllipse.cpp b/experimental/svg/model/SkSVGEllipse.cpp
index a70a8e0..f7461b8 100644
--- a/experimental/svg/model/SkSVGEllipse.cpp
+++ b/experimental/svg/model/SkSVGEllipse.cpp
@@ -63,6 +63,6 @@
     const auto ry = lctx.resolve(fRy, SkSVGLengthContext::LengthType::kVertical);
 
     if (rx > 0 && ry > 0) {
-        canvas->drawOval(SkRect::MakeXYWH(cx - rx / 2, cy - ry / 2, rx * 2, ry * 2), paint);
+        canvas->drawOval(SkRect::MakeXYWH(cx - rx, cy - ry, rx * 2, ry * 2), paint);
     }
 }