Remove some InterfacePtr<> methods which directly deal with message pipe handles.

mojo/public/cpp/application/lib/application_test_base.cc

 // 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.
 
 #include "mojo/public/cpp/application/application_test_base.h"
 
 #include "mojo/public/cpp/application/application_impl.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/environment/environment.h"
 #include "mojo/public/cpp/system/message_pipe.h"
@@ skipping 97 matching lines @@
     testing::InitGoogleTest(&argc, const_cast<char**>(&(argv[0])));
     InitializeArgs(argc, argv);
 
     Environment::DestroyDefaultRunLoop();
   }
 
   int result = RUN_ALL_TESTS();
 
   // Shut down our message pipes before exiting.
   (void)g_application_request.PassMessagePipe();
-  (void)g_shell.PassMessagePipe();
+  (void)g_shell.PassInterface();
 
   return (result == 0) ? MOJO_RESULT_OK : MOJO_RESULT_UNKNOWN;
 }
 
 ApplicationTestBase::ApplicationTestBase() : application_impl_(nullptr) {
 }
 
 ApplicationTestBase::~ApplicationTestBase() {
 }
 
@@ skipping 27 matching lines @@
   if (ShouldCreateDefaultRunLoop())
     Environment::DestroyDefaultRunLoop();
 }
 
 bool ApplicationTestBase::ShouldCreateDefaultRunLoop() {
   return true;
 }
 
 }  // namespace test
 }  // namespace mojo