Move MimeMultipartTransformer and HttpBodyHandler to mime and http_server packages.

sdk/lib/_internal/pub/lib/src/utils.dart

 // Copyright (c) 2012, 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.
 
 /// Generic utility functions. Stuff that should possibly be in core.
 library pub.utils;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
@@ skipping 485 matching lines @@
 /// Returns whether [error] is a user-facing error object. This includes both
 /// [ApplicationException] and any dart:io errors.
 bool isUserFacingException(error) {
   return error is ApplicationException ||
     // TODO(nweiz): clean up this branch when issue 9955 is fixed.
     error is DirectoryException ||
     error is FileException ||
     error is HttpException ||
     error is HttpException ||
     error is LinkException ||
-    error is MimeMultipartException ||
     error is OSError ||
     error is ProcessException ||
     error is SocketException ||
     error is WebSocketException;
 }