Remove usage of dart:json.

editor/tools/plugins/com.google.dart.tools.core_test/src-dart/pub_package_server.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.
 
 /// Runs a HTTP server on localhost that mimics the behavoir of pub.dartlang.org
 /// and serves files on pub requests. Files to be stored are on disk in the file
 /// system.
 ///
 /// The port for the server and the base directory of the data to be served
 /// should be passed in as arguments
 
 library pub_package_server;
 
 import 'dart:async';
 import 'dart:io';
-import 'dart:json' as json;
 
 const LOG_REQUESTS = true;
 
 String baseDir;
 
 main() {
   int port;
   var options = new Options().arguments;
   if (options.length != 1) {
     print('Insufficient arguments \npub_package_server serverDataLocation');
@@ skipping 39 matching lines @@
       response.close();
     });
   } catch (e) {
     print(e);
     response.statusCode = 500;
     response.close();
     return;
   }
 }