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

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

Index: mojo/public/dart/third_party/barback/test/transformer/emit_nothing.dart
diff --git a/mojo/public/dart/third_party/barback/test/transformer/emit_nothing.dart b/mojo/public/dart/third_party/barback/test/transformer/emit_nothing.dart
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index 0000000000000000000000000000000000000000..9cf513446ea228c15ef205fb32abd188d2749dfa
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+// 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.emit_nothing;
+
+import 'package:barback/barback.dart';
+
+import 'mock.dart';
+
+/// A transformer that emits no assets.
+class EmitNothingTransformer extends MockTransformer {
+  final String extension;
+
+  EmitNothingTransformer(this.extension);
+
+  bool doIsPrimary(AssetId id) => id.extension == ".$extension";
+
+  void doApply(Transform transform) {
+    // Emit nothing.
+  }
+
+  String toString() => "$extension->nothing";
+}