Move shell service to toplevel shell namespace

services/shell/runner/host/in_process_native_runner_unittest.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 "services/shell/runner/host/in_process_native_runner.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace mojo {
 namespace shell {
 
 TEST(InProcessNativeRunnerTest, NotStarted) {
   InProcessNativeRunner runner;
   // Shouldn't crash or DCHECK on destruction.
 }
 
 }  // namespace shell
-}  // namespace mojo