Extract shell methods from ApplicationImpl into a base class, and pass this to Initialize() instead.

mojo/shell/runner/child/native_apptest.cc

 // 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.
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "mojo/converters/network/network_type_converters.h"
-#include "mojo/shell/public/cpp/application_impl.h"
 #include "mojo/shell/public/cpp/application_test_base.h"
 #include "mojo/shell/runner/child/test_native_service.mojom.h"
 
 namespace mojo {
 namespace shell {
 namespace {
 void InvertCallback(bool* result, bool from_native) {
   *result = from_native;
 }
 }  // namespace
 
 using NativeAppTest = mojo::test::ApplicationTestBase;
 
 TEST_F(NativeAppTest, Connect) {
   test::TestNativeServicePtr native_service;
-  application_impl()->ConnectToService(
-      "exe:mojo_runner_child_apptest_native_target", &native_service);
+  shell()->ConnectToService("exe:mojo_runner_child_apptest_native_target",
+                            &native_service);
 
   bool result = false;
   native_service->Invert(
       true, base::Bind(&InvertCallback, base::Unretained(&result)));
   native_service.WaitForIncomingResponse();
   EXPECT_FALSE(result);
 
   native_service->Invert(
       false, base::Bind(&InvertCallback, base::Unretained(&result)));
   native_service.WaitForIncomingResponse();
   EXPECT_TRUE(result);
 }
 
 }  // namespace shell
 }  // namespace mojo