Add scripts to generate simple test data for certificate verification.

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

Index: net/data/verify_certificate_chain_unittest/generate-expired-target-notBefore.py
diff --git a/net/data/verify_certificate_chain_unittest/generate-expired-target-notBefore.py b/net/data/verify_certificate_chain_unittest/generate-expired-target-notBefore.py
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index 0000000000000000000000000000000000000000..3ff7d63cb082bd00e0adb58f63315f1a0e39f10d
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+++ b/net/data/verify_certificate_chain_unittest/generate-expired-target-notBefore.py
@@ -0,0 +1,28 @@
+#!/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, where the target is expired (violates
+validity.notBefore). Verification is expected to fail."""
+
+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.
+target = common.create_end_entity_certificate('Target', intermediary)
+target.set_validity_range(common.JANUARY_1_2015_UTC, common.JANUARY_1_2016_UTC)
+
+chain = [target, intermediary]
+trusted = [root]
+
+# March 2nd, 2014 midnight UTC
+time = '140302120000Z'
+verify_result = False
+
+common.write_test_file(__doc__, chain, trusted, time, verify_result)