Extracted shell_interfaces and shell_public into a separate gyp file.

services/user/user.gyp

 # Copyright 2016 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.
 
 {
   'variables': {
     # This turns on e.g. the filename-based detection of which
     # platforms to include source files on (e.g. files ending in
     # _mac.h or _mac.cc are only compiled on MacOSX).
     'chromium_code': 1,
@@ skipping 13 matching lines @@
         'user_service.h',
         'user_shell_client.cc',
         'user_shell_client.h',
       ],
       'dependencies': [
         'user_app_manifest',
         'user_service_bindings',
         '../../base/base.gyp:base',
         '../../components/filesystem/filesystem.gyp:filesystem_lib',
         '../../components/leveldb/leveldb.gyp:leveldb_lib',
-        '../../services/shell/shell.gyp:shell_public',
+        '../../services/shell/shell_public.gyp:shell_public',
         '../../services/tracing/tracing.gyp:tracing_lib',
         '../../mojo/mojo_edk.gyp:mojo_system_impl',
         '../../mojo/mojo_public.gyp:mojo_cpp_bindings',
         '../../mojo/mojo_platform_handle.gyp:platform_handle',
         '../../url/url.gyp:url_lib',
       ],
       'export_dependent_settings': [
         'user_service_bindings',
       ],
     },
@@ skipping 41 matching lines @@
         'application_name': 'user',
         'source_manifest': '<(DEPTH)/services/user/manifest.json',
       },
       'includes': [
         '../../mojo/public/mojo_application_manifest.gypi',
       ],
       'hard_dependency': 1,
     },
   ],
 }