Revert "app_shell: Add experimental shellPrivate extension API"

extensions/common/api/schemas.gypi

 # 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.
 
 {
   'sources': [
     '<@(schema_files)',
   ],
   'variables': {
     'chromium_code': 1,
@@ skipping 12 matching lines @@
       'events.json',
       'extensions_manifest_types.json',
       'extension_options_internal.idl',
       'extension_types.json',
       'guest_view_internal.json',
       'hid.idl',
       'mime_handler_view_guest_internal.json',
       'power.idl',
       'runtime.json',
       'serial.idl',
-      'shell_private.idl',
       'socket.idl',
       'sockets_tcp.idl',
       'sockets_tcp_server.idl',
       'sockets_udp.idl',
       'storage.json',
       'system_cpu.idl',
       'system_display.idl',
       'system_memory.idl',
       'system_network.idl',
       'system_storage.idl',
@@ skipping 21 matching lines @@
       }, {
         'schema_files': [
         ],
       }],
     ],
     'cc_dir': 'extensions/common/api',
     'root_namespace': 'extensions::core_api::%(namespace)s',
     'impl_dir_': 'extensions/browser/api',
   },
 }