[SVGDom] Add <line> support

R=robertphillips@google.com,stephana@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2244223005

Review-Url: https://codereview.chromium.org/2244223005
diff --git a/BUILD.gn b/BUILD.gn
index 1f43ca1..b18cdd4 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -534,6 +534,7 @@
     "experimental/svg/model/SkSVGCircle.cpp",
     "experimental/svg/model/SkSVGDOM.cpp",
     "experimental/svg/model/SkSVGEllipse.cpp",
+    "experimental/svg/model/SkSVGLine.cpp",
     "experimental/svg/model/SkSVGNode.cpp",
     "experimental/svg/model/SkSVGPath.cpp",
     "experimental/svg/model/SkSVGPoly.cpp",