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

mojo/public/dart/third_party/async/lib/src/result_future.dart

Index: mojo/public/dart/third_party/async/lib/src/result_future.dart
diff --git a/mojo/public/dart/third_party/async/lib/src/result_future.dart b/mojo/public/dart/third_party/async/lib/src/result_future.dart
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+// Copyright (c) 2015, 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 async.result_future;
+
+import 'dart:async';
+
+import '../result.dart';
+import 'delegate/future.dart';
+
+/// A [Future] wrapper that provides synchronous access to the result of the
+/// wrapped [Future] once it's completed.
+class ResultFuture<T> extends DelegatingFuture<T> {
+  /// Whether the future has fired and [result] is available.
+  bool get isComplete => result != null;
+
+  /// The result of the wrapped [Future], if it's completed.
+  ///
+  /// If it hasn't completed yet, this will be `null`.
+  Result<T> get result => _result;
+  Result<T> _result;
+
+  factory ResultFuture(Future<T> future) {
+    var resultFuture;
+    resultFuture = new ResultFuture._(Result.capture(future).then((result) {
+      resultFuture._result = result;
+      return result.asFuture;
+    }));
+    return resultFuture;
+  }
+
+  ResultFuture._(Future<T> future)
+      : super(future);
+}