Mojo: Add a trivial end-to-end (in-process) test of Mojo shell.

mojo/services/test_service/test_service_impl.cc

Index: mojo/services/test_service/test_service_impl.cc
diff --git a/mojo/shell/shell_test_base.cc b/mojo/services/test_service/test_service_impl.cc
similarity index 52%
copy from mojo/shell/shell_test_base.cc
copy to mojo/services/test_service/test_service_impl.cc
index f258af474622e89d53bf720e298ac202fe07c7c6..b4e9c35dc97d53ce1691b7fe3d683f806dbbfc6e 100644
--- a/mojo/shell/shell_test_base.cc
+++ b/mojo/services/test_service/test_service_impl.cc
@@ -2,18 +2,20 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "mojo/shell/shell_test_base.h"
+#include "mojo/services/test_service/test_service_impl.h"
 
 namespace mojo {
-namespace shell {
 namespace test {
 
-ShellTestBase::ShellTestBase() {
+TestServiceImpl::TestServiceImpl() {
 }
 
-ShellTestBase::~ShellTestBase() {
+TestServiceImpl::~TestServiceImpl() {
+}
+
+void TestServiceImpl::Ping(const mojo::Callback<void()>& callback) {
+  callback.Run();
 }
 
 }  // namespace test
-}  // namespace shell
 }  // namespace mojo