Cache .so files for debugging per device and don't redownload .so's that are in your cache

sky/tools/android_library_cacher.py

 #!/usr/bin/env python
 # Copyright 2015 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.
 
 import argparse
 import logging
 import os
 import re
 import skypy.paths
@@ skipping 39 matching lines @@
 
     dev_null = open(os.devnull, 'w')  # Leaking.
     to_pull = set(filter(None, map(library_from_line, maps_lines)))
     to_pull.add('/system/bin/linker')  # Unclear why but adb_gdb pulls this too.
     for library_path in sorted(to_pull):
         # Not using os.path.join since library_path is absolute.
         dest_file = os.path.normpath("%s/%s" % (args.cache_root, library_path))
         dest_dir = os.path.dirname(dest_file)
         if not os.path.exists(dest_dir):
             os.makedirs(dest_dir)
+        if os.path.exists(dest_file):
+            continue
         print '%s -> %s' % (library_path, dest_file)
         pull_cmd = [ADB_PATH, 'pull', library_path, dest_file]
         subprocess.check_call(pull_cmd, stderr=dev_null)
 
 
 if __name__ == '__main__':
     main()