Add modified time checking to strip_library_for_apk.py

build/android/gyp/strip_library_for_apk.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.
 
 import json
 import optparse
 import os
 import sys
 
 from util import build_utils
 
 
 def StripLibrary(android_strip, android_strip_args, library_path, output_path):
-  strip_cmd = ([android_strip] +
-               android_strip_args +
-               ['-o', output_path, library_path])
-  build_utils.CheckCallDie(strip_cmd)
+  if build_utils.IsTimeStale(output_path, [library_path]):
+    strip_cmd = ([android_strip] +
+                 android_strip_args +
+                 ['-o', output_path, library_path])
+    build_utils.CheckCallDie(strip_cmd)
+
 
 
 def main(argv):
   parser = optparse.OptionParser()
 
   parser.add_option('--android-strip',
       help='Path to the toolchain\'s strip binary')
   parser.add_option('--android-strip-arg', action='append',
       help='Argument to be passed to strip')
   parser.add_option('--libraries-dir',
@@ skipping 18 matching lines @@
         options.stripped_libraries_dir, library)
     StripLibrary(options.android_strip, options.android_strip_arg, library_path,
         stripped_library_path)
 
   if options.stamp:
     build_utils.Touch(options.stamp)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))