Rationalize Dart mojo and sky package structure

services/dart/dart_apptests/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:mojo.io';
 
 import 'package:apptest/apptest.dart';
-import 'package:mojo/public/dart/application.dart';
-import 'package:mojo/public/dart/bindings.dart';
-import 'package:mojo/public/dart/core.dart';
+import 'package:mojo/application.dart';
+import 'package:mojo/bindings.dart';
+import 'package:mojo/core.dart';
 
 tests(Application application, String url) {
   group('Http Apptests', () {
     // Bind server to a random port.
     test('Http Server Bind', () async {
       var server = await HttpServer.bind(InternetAddress.LOOPBACK_IP_V4, 0);
       expect(server, isNotNull);
       expect(server.port, greaterThan(1024));
       await server.close();
     });
@@ skipping 38 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();
     });
   });
 }