[Android] add stamp option in delete_files.py.

build/android/gyp/delete_files.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 """Delete files in directories matching a pattern.
 """
 
 import glob
 import optparse
 import os
 import sys
 
+from util import build_utils
+
 def main():
   parser = optparse.OptionParser()
   parser.add_option(
       '--pattern',
       help='Pattern for matching Files to delete.')
   parser.add_option(
       '--keep',
       help='Files to keep even if they matches the pattern.')
+  parser.add_option(
+      '--stamp',
+      help='Path to touch on success')
 
   options, args = parser.parse_args()
 
   if not options.pattern or not args:
     print 'No --pattern or target directories given'
     return
 
   for target_dir in args:
     target_pattern = os.path.join(target_dir, options.pattern)
     matching_files = glob.glob(target_pattern)
 
     keep_pattern = os.path.join(target_dir, options.keep)
     files_to_keep = glob.glob(keep_pattern)
 
     for target_file in matching_files:
       if target_file in files_to_keep:
         continue
 
       if os.path.isfile(target_file):
         os.remove(target_file)
 
+  if options.stamp:
+    build_utils.Touch(options.stamp)
+
 if __name__ == '__main__':
   sys.exit(main())