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

mojo/public/dart/third_party/barback/test/transformer/lazy_rewrite.dart

Index: mojo/public/dart/third_party/barback/test/transformer/lazy_rewrite.dart
diff --git a/mojo/public/dart/third_party/barback/test/transformer/lazy_rewrite.dart b/mojo/public/dart/third_party/barback/test/transformer/lazy_rewrite.dart
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index 0000000000000000000000000000000000000000..63bffb607a1ff6f456fb0ce5149180b049a15fbf
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+++ b/mojo/public/dart/third_party/barback/test/transformer/lazy_rewrite.dart
@@ -0,0 +1,17 @@
+// Copyright (c) 2014, 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 barback.test.transformer.lazy_rewrite;
+
+import 'package:barback/barback.dart';
+
+import 'declaring_rewrite.dart';
+
+/// Like [RewriteTransformer], but returns a lazy asset that doesn't perform the
+/// rewrite until it's materialized.
+class LazyRewriteTransformer extends DeclaringRewriteTransformer
+    implements LazyTransformer {
+  LazyRewriteTransformer(String from, String to)
+      : super(from, to);
+}