Tests for premature GC of custom elements within template contents

tests/html/custom/template_wrappers_test.dart

Index: tests/html/custom/template_wrappers_test.dart
diff --git a/tests/html/custom/template_wrappers_test.dart b/tests/html/custom/template_wrappers_test.dart
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+// Copyright (c) 2013, 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.
+
+library template_wrappers_test;
+
+import 'dart:async';
+import 'dart:html';
+import 'dart:js' as js;
+import 'package:unittest/html_config.dart';
+import 'package:unittest/unittest.dart';
+import '../utils.dart';
+
+int createdCount = 0;
+
+class CustomElement extends HtmlElement {
+  CustomElement.created() : super.created() {
+    ++createdCount;
+  }
+
+  void checkCreated() {
+  }
+}
+
+// Pump custom events polyfill events.
+void customElementsTakeRecords() {
+  if (js.context != null && js.context.hasProperty('CustomElements')) {
+    js.context['CustomElements'].callMethod('takeRecords');
+  }
+}
+
+main() {
+  useHtmlConfiguration();
+
+  var registeredTypes = false;
+  setUp(loadPolyfills);
+
+  test('element is upgraded once', () {
+
+    expect(createdCount, 0);
+    document.register('x-custom', CustomElement);
+    expect(createdCount, 1);
+
+    forceGC();
+
+    return new Future.delayed(new Duration(milliseconds: 50)).then((_) {
+      var t = document.querySelector('.t1');
+
+      var fragment = t.content;
+
+      fragment.querySelector('x-custom').checkCreated();
+      expect(createdCount, 1);
+    });
+  });
+}
+
+
+void forceGC() {
+  var N = 1000000;
+  var M = 1000;
+  for (var i = 0; i < M; ++i) {
+    var l = new List(N);
+  }
+}