Dart: Reorganize files

mojo/dart/apptests/dart_apptests/lib/src/io_http_apptests.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 library io_http_apptests;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ skipping 52 matching lines @@
       expect(response, isNotNull);
       expect(response.statusCode, equals(HttpStatus.OK));
       // Reduce to a single list.
       var payload = await response.reduce((p, e) => p..addAll(e));
       // Verify payload is correct.
       expect('contents of bar.txt', equals(UTF8.decode(payload)));
       await server.close();
     });
   });
 }