Add support for system snappy.

build/linux/unbundle/replace_gyp_files.py

 #!/usr/bin/env python
 # Copyright 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.
 
 """
 Replaces gyp files in tree with files from here that
 make the build use system libraries.
 """
 
@@ skipping 13 matching lines @@
   'use_system_libevent': 'third_party/libevent/libevent.gyp',
   'use_system_libjpeg': 'third_party/libjpeg/libjpeg.gyp',
   'use_system_libpng': 'third_party/libpng/libpng.gyp',
   'use_system_libusb': 'third_party/libusb/libusb.gyp',
   'use_system_libvpx': 'third_party/libvpx/libvpx.gyp',
   'use_system_libwebp': 'third_party/libwebp/libwebp.gyp',
   'use_system_libxml': 'third_party/libxml/libxml.gyp',
   'use_system_libxslt': 'third_party/libxslt/libxslt.gyp',
   'use_system_opus': 'third_party/opus/opus.gyp',
   'use_system_re2': 'third_party/re2/re2.gyp',
+  'use_system_snappy': 'third_party/snappy/snappy.gyp',
   'use_system_speex': 'third_party/speex/speex.gyp',
   'use_system_sqlite': 'third_party/sqlite/sqlite.gyp',
   'use_system_v8': 'v8/tools/gyp/v8.gyp',
   'use_system_zlib': 'third_party/zlib/zlib.gyp',
 }
 
 
 def DoMain(argv):
   my_dirname = os.path.dirname(__file__)
   source_tree_root = os.path.abspath(
     os.path.join(my_dirname, '..', '..', '..'))
 
   for flag, path in REPLACEMENTS.items():
     # Accept arguments in gyp command-line syntax, and ignore other
     # parameters, so that the caller can re-use command-line for this
     # script and gyp.
     if '-D%s=1' % flag not in argv:
       continue
 
     # Copy the gyp file from directory of this script to target path.
     shutil.copyfile(os.path.join(my_dirname, os.path.basename(path)),
                     os.path.join(source_tree_root, path))
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(DoMain(sys.argv))