Separate mojo/shell into a runner and the application manager (shell)

mojo/shell/desktop/main.cc

-// Copyright 2013 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/at_exit.h"
-#include "base/command_line.h"
-#include "mojo/shell/child_process.h"
-#include "mojo/shell/desktop/launcher_process.h"
-#include "mojo/shell/init.h"
-#include "mojo/shell/switches.h"
-
-int main(int argc, char** argv) {
-  base::AtExitManager at_exit;
-  base::CommandLine::Init(argc, argv);
-
-  mojo::shell::InitializeLogging();
-
-  const base::CommandLine& command_line =
-      *base::CommandLine::ForCurrentProcess();
-  if (command_line.HasSwitch(switches::kChildProcess))
-    return mojo::shell::ChildProcessMain();
-
-  return mojo::shell::LauncherProcessMain(argc, argv);
-}