Fix mirror_loader to detect whether the type is a generic class.

pkg/polymer/test/mirror_loader_test.dart

+// 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.
+
+import 'dart:async';
+import 'dart:html';
+
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+import 'package:polymer/polymer.dart';
+
+@CustomTag('x-a')
+class XA extends PolymerElement {
+  final String x = "a";
+  XA.created() : super.created();
+}
+
+// The next classes are here as a regression test for darbug.com/17929. Our
+// loader was incorrectly trying to retrieve the reflectiveType of these
+// classes.
+class Foo<T> {}
+
+@CustomTag('x-b')
+class XB<T> extends PolymerElement {
+  final String x = "a";
+  XB.created() : super.created();
+}
+
+main() {
+  useHtmlConfiguration();
+
+  runZoned(() {
+    initPolymer().run(() {
+      setUp(() => Polymer.onReady);
+
+      test('XA was registered correctly', () {
+        expect(querySelector('x-a').shadowRoot.nodes.first.text, 'a');
+      });
+
+      test('XB was not registered', () {
+        expect(querySelector('x-b').shadowRoot, null);
+      });
+    });
+  }, onError: (e) {
+    expect(e is UnsupportedError, isTrue);
+    expect('$e', contains(
+        'Custom element classes cannot have type-parameters: XB'));
+  });
+}