Removed unused mojo_nacl code and GYP targets.

mojo/nacl/monacl_shell.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 <iostream>
-
-#include "mojo/edk/embedder/embedder.h"
-#include "mojo/edk/embedder/simple_platform_support.h"
-#include "mojo/nacl/monacl_sel_main.h"
-
-
-int main(int argc, char* argv[]) {
-  if (argc < 3) {
-    std::cout << "Usage: " << argv[0] << " irt.nexe app.nexe [args for app]" <<
-        std::endl;
-    return 1;
-  }
-
-  const char* irt_file = argv[1];
-  const char* nexe_file = argv[2];
-
-  mojo::embedder::Init(scoped_ptr<mojo::embedder::PlatformSupport>(
-      new mojo::embedder::SimplePlatformSupport()));
-
-  // Does not return.
-  mojo::LaunchNaCl(nexe_file, irt_file, argc - 2, argv + 2);
-  return 1;
-}