Add scripts to generate simple test data for certificate verification.

net/data/verify_certificate_chain_unittest/generate-target-unknown-critical-extension.py

Index: net/data/verify_certificate_chain_unittest/generate-target-unknown-critical-extension.py
diff --git a/net/data/verify_certificate_chain_unittest/generate-target-unknown-critical-extension.py b/net/data/verify_certificate_chain_unittest/generate-target-unknown-critical-extension.py
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index 0000000000000000000000000000000000000000..725429920c838b1ba36d7c733479098212922848
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+++ b/net/data/verify_certificate_chain_unittest/generate-target-unknown-critical-extension.py
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+#!/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 intermediary and a trusted root. The target
+certificate has an unknown X.509v3 extension (OID=1.2.3.4) that is marked as
+critical. Verifying this certificate chain is expected to fail because there is
+an unrecognized critical extension."""
+
+import common
+
+# Self-signed root certificate (part of trust store).
+root = common.create_self_signed_root_certificate('Root')
+
+# Intermediary certificate.
+intermediary = common.create_intermediary_certificate('Intermediary', root)
+
+# Target certificate (has unknown critical extension).
+target = common.create_end_entity_certificate('Target', intermediary)
+target.get_extensions().add_property('1.2.3.4',
+                                     'critical,DER:01:02:03:04')
+
+chain = [target, intermediary]
+trusted = [root]
+time = common.DEFAULT_TIME
+verify_result = False
+
+common.write_test_file(__doc__, chain, trusted, time, verify_result)