Fix GN auto-roller to handle results from buildbucket-initiated jobs.

tools/gn/bin/roll_gn.py

 # Copyright 2014 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.
 
 """An auto-roller for GN binaries into Chromium.
 
 This script is used to update the GN binaries that a Chromium
 checkout uses. In order to update the binaries, one must follow
 four steps in order:
 
@@ skipping 192 matching lines @@
       raise
 
     patchset = int(props['patchsets'][-1])
 
     try:
       patchset_data = json.loads(rpc_server.Send('/api/%d/%d' %
                                                  (issue, patchset)))
     except Exception as _e:
       raise
 
-    TRY_JOB_RESULT_STATES = ('success', 'warnings', 'failure', 'skipped',
-                             'exception', 'retry', 'pending')
     try_job_results = patchset_data['try_job_results']
     if not try_job_results:
       print('No try jobs found on most recent patchset')
       return 1
 
     results = {}
     for job in try_job_results:
       builder = job['builder']
       if builder == 'linux_chromium_gn_upload':
         platform = 'linux64'
       elif builder == 'mac_chromium_gn_upload':
         platform = 'mac'
       elif builder == 'win8_chromium_gn_upload':
         platform = 'win'
       else:
         print('Unexpected builder: %s')
         continue
 
-      state = TRY_JOB_RESULT_STATES[int(job['result'])]
+      TRY_JOB_RESULT_STATES = ('started', 'success', 'warnings', 'failure',
+                               'skipped', 'exception', 'retry', 'pending')
+      state = TRY_JOB_RESULT_STATES[int(job['result']) + 1]
       url_str = ' %s' % job['url']
       build = url_str.split('/')[-1]
 
       sha1 = '-'
       results.setdefault(platform, {'build': -1, 'sha1': '', 'url': url_str})
 
       if state == 'success':
         jsurl = url_str.replace('/builders/', '/json/builders/')
         fp = urllib2.urlopen(jsurl)
         js = json.loads(fp.read())
@@ skipping 161 matching lines @@
   def Call(self, cmd, cwd=None):
     proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, shell=True,
                             cwd=(cwd or self.chromium_src_dir))
     out, err = proc.communicate()
     return proc.returncode, out, err
 
 
 if __name__ == '__main__':
   roller = GNRoller()
   sys.exit(roller.Roll())