Update comments for net/data/verify_certificate_chain_unittest/

net/data/verify_certificate_chain_unittest/non-self-signed-root/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 and a trusted root. The trusted root
-is NOT self signed, however its issuer is not included in the chain or root
-store. Verification is expected to succeed since the root is trusted."""
+"""Certificate chain where the root certificate is not self-signed (or
+self-issued for that matter)."""
 
 import sys
 sys.path += ['..']
 
 import common
 
 shadow_root = common.create_self_signed_root_certificate('ShadowRoot')
 
-# Non-self-signed root (part of trust store).
+# Non-self-signed root certificate.
 root = common.create_intermediate_certificate('Root', shadow_root)
 
 # Intermediate certificate.
 intermediate = common.create_intermediate_certificate('Intermediate', root)
 
 # Target certificate.
 target = common.create_end_entity_certificate('Target', intermediate)
 
 chain = [target, intermediate, root]
 common.write_chain(__doc__, chain, 'chain.pem')