[Android] Sanitize APK signing file timestamps.

build/android/gyp/finalize_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.
 """Signs and zipaligns APK.
 
 """
 
 import optparse
 import shutil
 import sys
 import tempfile
+import zipfile
 
 from util import build_utils
 
 def RenameInflateAndAddPageAlignment(
     rezip_apk_jar_path, in_zip_file, out_zip_file):
   rezip_apk_cmd = [
       'java',
       '-classpath',
       rezip_apk_jar_path,
       'RezipApk',
@@ skipping 112 matching lines @@
       apk_to_sign = apk_to_sign_tmp.name
       RenameInflateAndAddPageAlignment(
           options.rezip_apk_jar_path, options.unsigned_apk_path, apk_to_sign)
     else:
       apk_to_sign = options.unsigned_apk_path
 
     signed_apk_path = signed_apk_path_tmp.name
     JarSigner(options.key_path, options.key_name, options.key_passwd,
               apk_to_sign, signed_apk_path)
 
+    # Make the signing files hermetic.
+    with tempfile.NamedTemporaryFile(suffix='.zip') as hermetic_signed_apk:
+      with zipfile.ZipFile(signed_apk_path, 'r') as zi:
+        with zipfile.ZipFile(hermetic_signed_apk, 'w') as zo:
+          for info in zi.infolist():
+            info.date_time = build_utils.HERMETIC_TIMESTAMP
+            zo.writestr(info, zi.read(info.filename))
+      shutil.copy(hermetic_signed_apk.name, signed_apk_path)
+
     if options.load_library_from_zip:
       # Reorder the contents of the APK. This re-establishes the canonical
       # order which means the library will be back at its page aligned location.
       # This step also aligns uncompressed items to 4 bytes.
       ReorderAndAlignApk(
           options.rezip_apk_jar_path, signed_apk_path, options.final_apk_path)
     else:
       # Align uncompressed items to 4 bytes
       AlignApk(options.zipalign_path,
                options.page_align_shared_libraries,
                signed_apk_path,
                options.final_apk_path)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))