Force inclusion of build/common.gypi for all chromium gyp files.

third_party/npapi/npapi.gyp

 # Copyright (c) 2009 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.
 
 {
-  'includes': [
-    '../../build/common.gypi',
-  ],
   'targets': [
     {
       'target_name': 'npapi',
       'type': 'none',
       'direct_dependent_settings': {
         'include_dirs': [
           # Some things #include "bindings/npapi.h" and others just #include
           # "npapi.h".  Account for both flavors.
           '.',
           'bindings',
         ],
       },
     },
   ],
 }