Fix editor warnings in http_server and mime.

pkg/http_server/lib/src/http_body.dart

 // Copyright (c) 2013, 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.
 
 part of http_server;
 
 
 /**
  * [HttpBodyHandler] is a helper class for processing and collecting
  * HTTP message data in an easy-to-use [HttpBody] object. The content
@@ skipping 205 matching lines @@
 
 
 /**
  * A [HttpBodyFileUpload] object wraps a file upload, presenting a way for
  * extracting filename, contentType and the data of the uploaded file.
  */
 abstract class HttpBodyFileUpload {
   /**
    * The filename of the uploaded file.
    */
-  String filename;
+  String get filename;
 
   /**
    * The [ContentType] of the uploaded file. For 'text/\*' and
    * 'application/json' the [data] field will a String.
    */
-  ContentType contentType;
+  ContentType get contentType;
 
   /**
    * The content of the file. Either a [String] or a [List<int>].
    */
-  dynamic content;
+  dynamic get content;
 }