Add relative path support.

verification/project_base.py

 # coding=utf8
 # Copyright (c) 2011 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.
 """Ignores issues not using the right project base url regex."""
 
 import logging
+import os
 import re
 
+import find_depot_tools  # pylint: disable=W0611
+import breakpad
+
 from verification import base
 
 
 class ProjectBaseUrlVerifier(base.Verifier):
   """Needs the project base url to match at least one regexp in self.regex."""
   name = 'project_bases'
 
   def __init__(self, project_bases):
     super(ProjectBaseUrlVerifier, self).__init__()
     self.project_bases = project_bases
 
   def verify(self, pending, revision):
-    if not any(re.match(r, pending.base_url) for r in self.project_bases):
+    matches = filter(
+        None, (re.match(r, pending.base_url) for r in self.project_bases))
+    if not matches:
       logging.info('%s not in whitelist' % pending.base_url)
       state = base.IGNORED
     else:
+      if len(matches) != 1:
+        breakpad.SendStack(
+            Exception('pending.base_url triggered multiple matches'), '')
+      match = matches[0]
+      if match.lastindex:
+        pending.relpath = match.group(match.lastindex).lstrip('/').replace(
+            '/', os.sep)
       state = base.SUCCEEDED
     pending.verifications[self.name] = base.SimpleStatus(state)
 
   def update_status(self, queue):
     pass