Added setNodeAttribute to SkSVGDom

Change-Id: Ib96c185aab9167116d20ca8d91a1703683cbf7dc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/288620
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
diff --git a/experimental/svg/model/SkSVGDOM.h b/experimental/svg/model/SkSVGDOM.h
index 3d097cc..c565913 100644
--- a/experimental/svg/model/SkSVGDOM.h
+++ b/experimental/svg/model/SkSVGDOM.h
@@ -31,6 +31,9 @@
 
     void setRoot(sk_sp<SkSVGNode>);
 
+    // Returns the node with the given id, or nullptr if not found.
+    sk_sp<SkSVGNode>* findNodeById(const char* id);
+
     void render(SkCanvas*) const;
 
 private: