[GN]: Fix bug in roller script with try servers

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 188 matching lines @@
     email = ''
     rpc_server = upload.GetRpcServer(CODE_REVIEW_SERVER, email)
     try:
       props = json.loads(rpc_server.Send('/api/%d' % issue))
     except Exception as _e:
       raise
 
     patchset = int(props['patchsets'][-1])
 
     try:
-      patchset_data = json.loads(rpc_server.Send('/api/%d/%d' %
-                                                 (issue, patchset)))
+      try_job_results = json.loads(rpc_server.Send(
+          '/api/%d/%d/try_job_results' % (issue, patchset)))
     except Exception as _e:
       raise
 
-    try_job_results = patchset_data['try_job_results']
     if not try_job_results:
       print('No try jobs found on most recent patchset')
       return {}
 
     results = {}
     for job in try_job_results:
       builder = job['builder']
       if builder == 'linux_chromium_gn_upload':
         platform = 'linux64'
       elif builder == 'mac_chromium_gn_upload':
@@ skipping 143 matching lines @@
         self.old_gn_version,
         self.new_gn_version,
         gn_changes,
         self.reviewer,
       ))
 
   def GetDEPSRollDesc(self, old_buildtools_commitish, new_buildtools_commitish):
     gn_changes = self.GetGNChanges()
 
     return (
-      'Roll DEPS %s..%s\n'
+      'Roll buildtools %s..%s\n'
       '\n'
       '  In order to roll GN %s..%s (r%s:r%s) and pick up\n'
       '  the following changes:\n'
       '\n'
       '%s'
       '\n'
       'TBR=%s\n'
       'CQ_EXTRA_TRYBOTS=tryserver.chromium.mac:mac_chromium_gn_rel,'
       'mac_chromium_gn_dbg;'
       'tryserver.chromium.win:win8_chromium_gn_dbg,'
@@ skipping 17 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())