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diff --git a/js/public/UbiNodeUtils.h b/js/public/UbiNodeUtils.h
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+++ b/js/public/UbiNodeUtils.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef js_UbiNodeUtils_h
+#define js_UbiNodeUtils_h
+
+#include "jspubtd.h"
+
+#include "js/UbiNode.h"
+#include "js/UniquePtr.h"
+
+using JS::ubi::Edge;
+using JS::ubi::EdgeRange;
+using JS::ubi::EdgeVector;
+
+namespace JS {
+namespace ubi {
+// An EdgeRange concrete class that simply holds a vector of Edges,
+// populated by the addTracerEdges method.
+class SimpleEdgeRange : public EdgeRange {
+  EdgeVector edges;
+  size_t i;
+
+ protected:
+  void settle() { front_ = i < edges.length() ? &edges[i] : nullptr; }
+
+ public:
+  explicit SimpleEdgeRange() : edges(), i(0) {}
+
+  bool addTracerEdges(JSRuntime* rt, void* thing, JS::TraceKind kind,
+                      bool wantNames);
+
+  bool addEdge(Edge edge) {
+    if (!edges.append(std::move(edge))) return false;
+    settle();
+    return true;
+  }
+
+  void popFront() override {
+    i++;
+    settle();
+  }
+};
+
+}  // namespace ubi
+}  // namespace JS
+
+#endif  // js_UbiNodeUtils_h