Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/unittest/test/completion_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.
+
+library unittest.completion_test;
+
+import 'dart:async';
+
+import 'package:metatest/metatest.dart';
+import 'package:unittest/unittest.dart';
+
+void main() => initTests(_test);
+
+void _test(message) {
+  initMetatest(message);
+
+  expectTestsPass('completion test', () {
+    var count = 0;
+    test('test', () {
+      var _callback;
+      _callback = expectAsyncUntil(() {
+        if (++count < 10) {
+          new Future.sync(_callback);
+        }
+      }, () => (count == 10));
+      new Future.sync(_callback);
+    });
+
+    test('verify count', () {
+      expect(count, 10);
+    });
+  });
+}