Make changes to mini_installer test files trigger tests.

chrome/tools/build/win/touch_sentinel.py

+# 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 os
+import sys
+
+def main(args):
+  """Touches a file.
+
+  Args:
+    args: An argument list, the first item of which is a file to touch.
+  """
+  try:
+    os.makedirs(os.path.dirname(args[0]))
+  except OSError:
+    pass
+  with open(args[0], 'a'):
+    os.utime(args[0], None)
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))