Wrapping leaf nodes in non polymer elements

runtime/observatory/lib/src/mocks/objects/source_location.dart

Index: runtime/observatory/lib/src/mocks/objects/source_location.dart
diff --git a/runtime/observatory/lib/src/mocks/objects/source_location.dart b/runtime/observatory/lib/src/mocks/objects/source_location.dart
new file mode 100644
index 0000000000000000000000000000000000000000..5f56e997051b5ea6195350279f0c7ab1a6cdf9ac
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+++ b/runtime/observatory/lib/src/mocks/objects/source_location.dart
@@ -0,0 +1,13 @@
+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file
+
+part of mocks;
+
+class SourceLocationMock implements M.SourceLocation {
+  final M.ScriptRef script;
+  final int tokenPos;
+  final int endTokenPos;
+
+  SourceLocationMock({this.script, this.tokenPos, this.endTokenPos});
+}