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

mojo/public/dart/third_party/http_parser/lib/http_parser.dart

Index: mojo/public/dart/third_party/http_parser/lib/http_parser.dart
diff --git a/mojo/public/dart/third_party/http_parser/lib/http_parser.dart b/mojo/public/dart/third_party/http_parser/lib/http_parser.dart
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index 0000000000000000000000000000000000000000..77c75c0aa9e6bbc245c46dabf64430d0f77349f3
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+++ b/mojo/public/dart/third_party/http_parser/lib/http_parser.dart
@@ -0,0 +1,11 @@
+// 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 http_parser;
+
+export 'src/authentication_challenge.dart';
+export 'src/case_insensitive_map.dart';
+export 'src/http_date.dart';
+export 'src/media_type.dart';
+export 'src/web_socket.dart';