Eliminate mojo::Shell client lib class

mojo/shell/background/tests/background_shell_unittest.cc

 // Copyright 2016 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 "mojo/shell/background/background_shell.h"
 
 #include "base/run_loop.h"
 #include "mojo/shell/background/tests/test.mojom.h"
 #include "mojo/shell/background/tests/test_application_catalog_store.h"
+#include "mojo/shell/public/cpp/connector.h"
 #include "mojo/shell/public/cpp/shell_client.h"
 #include "mojo/shell/public/cpp/shell_connection.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 namespace mojo {
 namespace shell {
 namespace {
 
 const char kTestUrl[] = "mojo:test-app";
@@ skipping 28 matching lines @@
   scoped_ptr<TestApplicationCatalogStore> store_ptr =
       BuildTestApplicationCatalogStore();
   TestApplicationCatalogStore* store = store_ptr.get();
   init_params->app_catalog = std::move(store_ptr);
   background_shell.Init(std::move(init_params));
   ShellClientImpl shell_client;
   ShellConnection shell_connection(
       &shell_client, background_shell.CreateShellClientRequest(GURL(kTestUrl)));
   shell_connection.WaitForInitialize();
   mojom::TestServicePtr test_service;
-  static_cast<Shell*>(&shell_connection)
-      ->ConnectToInterface("mojo:background_shell_test_app", &test_service);
+  shell_connection.connector()->ConnectToInterface(
+      "mojo:background_shell_test_app", &test_service);
   base::RunLoop run_loop;
   bool got_result = false;
   test_service->Test([&run_loop, &got_result]() {
     got_result = true;
     run_loop.Quit();
   });
   run_loop.Run();
   EXPECT_TRUE(got_result);
   EXPECT_TRUE(store->get_store_called());
 }
 
 }  // namespace shell
 }  // namespace mojo