Refactor how net/data/verify_certificate_chain_unittest/*

net/data/verify_certificate_chain_unittest/expired-target/generate-chains.py

 #!/usr/bin/python
 # Copyright (c) 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.
 
 """Certificate chain with 1 intermediate, where the target is expired (violates
 validity.notAfter). Verification is expected to fail."""
 
+import sys
+sys.path += ['..']
+
 import common
 
 # Self-signed root certificate (used as trust anchor).
 root = common.create_self_signed_root_certificate('Root')
 root.set_validity_range(common.JANUARY_1_2015_UTC, common.JANUARY_1_2016_UTC)
 
 # Intermediate certificate.
 intermediate = common.create_intermediate_certificate('Intermediate', root)
 intermediate.set_validity_range(common.JANUARY_1_2015_UTC,
                                 common.JANUARY_1_2016_UTC)
 
 # Target certificate.
 target = common.create_end_entity_certificate('Target', intermediate)
 target.set_validity_range(common.JANUARY_1_2015_UTC, common.MARCH_1_2015_UTC)
 
-chain = [target, intermediate]
-trusted = common.TrustAnchor(root, constrained=False)
 
 # Both the root and intermediate are valid at this time, however the
 # target is not.
-time = common.MARCH_2_2015_UTC
-key_purpose = common.DEFAULT_KEY_PURPOSE
-verify_result = False
-errors = """----- Certificate i=0 (CN=Target) -----
-ERROR: Time is after notAfter
 
-"""
-
-common.write_test_file(__doc__, chain, trusted, time, key_purpose,
-                       verify_result, errors)
+chain = [target, intermediate, root]
+common.write_chain(__doc__, chain, 'chain.pem')