[Android] Refactor md5_check + add tests

build/android/gyp/apk_install.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.
 
 """Installs an APK.
 
 """
 
@@ skipping 20 matching lines @@
       help='Path to touch on success.')
   options, _ = parser.parse_args()
 
   # TODO(cjhopman): Should this install to all devices/be configurable?
   install_cmd = [
       os.path.join(options.android_sdk_tools, 'adb'),
       'install', '-r',
       options.apk_path]
 
   serial_number = android_commands.AndroidCommands().Adb().GetSerialNumber()
-  md5_stamp = '%s.%s.md5' % (options.apk_path, serial_number)
-
-  md5_checker = md5_check.Md5Checker(
-      stamp=md5_stamp, inputs=[options.apk_path], command=install_cmd)
-  if md5_checker.IsStale():
-    build_utils.CheckCallDie(install_cmd)
-    md5_checker.Write()
+  record_path = '%s.%s.md5.stamp' % (options.apk_path, serial_number)
+  md5_check.CallAndRecordIfStale(
+      lambda: build_utils.CheckCallDie(install_cmd),
+      record_path=record_path,
+      input_paths=[options.apk_path],
+      input_strings=install_cmd)
 
   if options.stamp:
     build_utils.Touch(options.stamp)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))