[SVGDom] Initial <use> support

https://www.w3.org/TR/SVG/struct.html#UseElement

Change-Id: Id85c2648255dcd4763bf11c7bdb8b1490286f1e4
Reviewed-on: https://skia-review.googlesource.com/58260
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index a65a211..66ea0d8 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1185,6 +1185,7 @@
       "experimental/svg/model/SkSVGShape.cpp",
       "experimental/svg/model/SkSVGStop.cpp",
       "experimental/svg/model/SkSVGTransformableNode.cpp",
+      "experimental/svg/model/SkSVGUse.cpp",
       "experimental/svg/model/SkSVGValue.cpp",
     ]
     deps = [