Rationalize Dart mojo and sky package structure

mojo/dart/test/compile_all_interfaces_test.dart

 // Copyright 2014 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.
 
 // Make sure that we are generating valid Dart code for all mojom interface
 // tests.
 // vmoptions: --compile_all
 
 import 'dart:async';
 import 'dart:isolate';
 import 'dart:typed_data';
 
-import 'package:mojo/dart/testing/expect.dart';
-import 'package:mojo/public/dart/application.dart';
-import 'package:mojo/public/dart/bindings.dart';
-import 'package:mojo/public/dart/core.dart';
+import 'package:testing/expect.dart';
+import 'package:mojo/application.dart';
+import 'package:mojo/bindings.dart';
+import 'package:mojo/core.dart';
 import 'package:mojom/mojo/application.mojom.dart';
 import 'package:mojom/mojo/service_provider.mojom.dart';
 import 'package:mojom/mojo/shell.mojom.dart';
 import 'package:mojom/math/math_calculator.mojom.dart';
 import 'package:mojom/no_module.mojom.dart';
 import 'package:mojom/mojo/test/rect.mojom.dart';
 import 'package:mojom/regression_tests/regression_tests.mojom.dart';
 import 'package:mojom/sample/sample_factory.mojom.dart';
 import 'package:mojom/imported/sample_import2.mojom.dart';
 import 'package:mojom/imported/sample_import.mojom.dart';
 import 'package:mojom/sample/sample_interfaces.mojom.dart';
 import 'package:mojom/sample/sample_service.mojom.dart';
 import 'package:mojom/mojo/test/serialization_test_structs.mojom.dart';
 import 'package:mojom/mojo/test/test_structs.mojom.dart';
 import 'package:mojom/mojo/test/validation_test_interfaces.mojom.dart';
 
 int main() {
   return 0;
 }