autoroller: Add TBR= field and always update the checkout

tools/autoroller/roll_chromium_revision.py

 #!/usr/bin/env python
 # Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 """Script to roll chromium_revision in the WebRTC DEPS file."""
@@ skipping 241 matching lines @@
   current_cr_rev = current_cr_rev[0:7]
   new_cr_rev = new_cr_rev[0:7]
   rev_interval = '%s..%s' % (current_cr_rev, new_cr_rev)
 
   current_git_number = ParseCommitPosition(ReadRemoteCrCommit(current_cr_rev))
   new_git_number = ParseCommitPosition(ReadRemoteCrCommit(new_cr_rev))
   git_number_interval = '%s:%s' % (current_git_number, new_git_number)
 
   commit_msg = ['Roll chromium_revision %s (%s)' % (rev_interval,
                                                     git_number_interval)]
-
+  # TBR field will be empty unless in some custom cases, where some engineers
+  # are added.
+  tbr_authors = ''
   if changed_deps_list:
     commit_msg.append('\nRelevant changes:')
 
     for c in changed_deps_list:
       commit_msg.append('* %s: %s..%s' % (c.path, c.current_rev[0:7],
                                           c.new_rev[0:7]))
+      if 'libvpx' in c.path:
+        tbr_authors += 'marpan@webrtc.org, stefan@webrtc.org, '
 
     change_url = CHROMIUM_FILE_TEMPLATE % (rev_interval, 'DEPS')
     commit_msg.append('Details: %s' % change_url)
 
   if clang_change.current_rev != clang_change.new_rev:
     commit_msg.append('\nClang version changed %s:%s' %
                       (clang_change.current_rev, clang_change.new_rev))
     change_url = CHROMIUM_FILE_TEMPLATE % (rev_interval,
                                            CLANG_UPDATE_SCRIPT_URL_PATH)
     commit_msg.append('Details: %s' % change_url)
+    tbr_authors += 'pbos@webrtc.org'
   else:
     commit_msg.append('\nClang version was not updated in this roll.')
+  commit_msg.append('\nTBR=%s\n' % tbr_authors)
   return '\n'.join(commit_msg)
 
 
 def UpdateDeps(deps_filename, old_cr_revision, new_cr_revision):
   """Update the DEPS file with the new revision."""
   with open(deps_filename, 'rb') as deps_file:
     deps_content = deps_file.read()
   deps_content = deps_content.replace(old_cr_revision, new_cr_revision)
   with open(deps_filename, 'wb') as deps_file:
     deps_file.write(deps_content)
 
 def _IsTreeClean():
   stdout, _ = _RunCommand(['git', 'status', '--porcelain'])
   if len(stdout) == 0:
     return True
 
   logging.error('Dirty/unversioned files:\n%s', stdout)
   return False
 
 
 def _EnsureUpdatedMasterBranch(dry_run):
   current_branch = _RunCommand(
       ['git', 'rev-parse', '--abbrev-ref', 'HEAD'])[0].splitlines()[0]
   if current_branch != 'master':
     logging.error('Please checkout the master branch and re-run this script.')
     if not dry_run:
       sys.exit(-1)
 
   logging.info('Updating master branch...')
-  if not dry_run:
-    _RunCommand(['git', 'pull'])
+  _RunCommand(['git', 'pull'])
 
 
 def _CreateRollBranch(dry_run):
   logging.info('Creating roll branch: %s', ROLL_BRANCH_NAME)
   if not dry_run:
     _RunCommand(['git', 'checkout', '-b', ROLL_BRANCH_NAME])
 
 
 def _RemovePreviousRollBranch(dry_run):
   active_branch, branches = _GetBranches()
@@ skipping 82 matching lines @@
   _CreateRollBranch(opts.dry_run)
   UpdateDeps(deps_filename, current_cr_rev, opts.revision)
   _LocalCommit(commit_msg, opts.dry_run)
   _UploadCL(opts.dry_run)
   _LaunchTrybots(opts.dry_run, opts.skip_try)
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())