Adding a new component, Previews.

components/components.gyp

 # Copyright (c) 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.
 
 {
   '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 54 matching lines @@
     'omnibox.gypi',
     'onc.gypi',
     'open_from_clipboard.gypi',
     'os_crypt.gypi',
     'ownership.gypi',
     'password_manager.gypi',
     'plugins.gypi',
     'policy.gypi',
     'precache.gypi',
     'pref_registry.gypi',
+    'previews.gypi',
     'profile_metrics.gypi',
     'proxy_config.gypi',
     'query_parser.gypi',
     'rappor.gypi',
     'search.gypi',
     'search_engines.gypi',
     'search_provider_logos.gypi',
     'security_interstitials.gypi',
     'security_state.gypi',
     'sessions.gypi',
@@ skipping 116 matching lines @@
         'rlz.gypi',
       ],
     }],
     ['use_ash==1', {
       'includes': [
         'exo.gypi',
       ],
     }],
   ],
 }