Set rebaseline bot name/email in chromium repo via git config.

scripts/slave/recipes/infra/rebaseline_o_matic.py

 # 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.
 
 """Generates new baselines for Blink layout tests that need rebaselining.
 
 Intended to be called periodically. Syncs to the Blink repo and runs
 'webkit-patch auto-rebaseline', which processes entries in
 LayoutTests/TestExpectations that are marked with 'NeedsRebaseline'.
 
@@ skipping 12 matching lines @@
 
 
 def RunSteps(api):
   RIETVELD_REFRESH_TOKEN = '/creds/refresh_tokens/blink_rebaseline_bot_rietveld'
 
   api.gclient.set_config('chromium')
   api.bot_update.ensure_checkout(force=True)
 
   cwd = api.path['checkout'].join('third_party', 'WebKit')
 
+  # Changes should be committed and landed as the rebaseline bot role account.
+  api.git('config', 'user.name', 'Rebaseline Bot')
+  api.git('config', 'user.email', 'blink-rebaseline-bot@chromium.org')
+
   api.python('webkit-patch auto-rebaseline',
              cwd.join('Tools', 'Scripts', 'webkit-patch'),
              ['auto-rebaseline', '--verbose',
-             '--auth-refresh-token-json', RIETVELD_REFRESH_TOKEN,
-             '--commit-author',
-             'Rebaseline Bot <blink-rebaseline-bot@chromium.org>'],
+             '--auth-refresh-token-json', RIETVELD_REFRESH_TOKEN],
              cwd=cwd)
 
 
 def GenTests(api):
   yield (api.test('rebaseline_o_matic') +
          api.properties(mastername='chromium.infra.cron',
                         buildername='rebaseline-o-matic',
                         slavename='fake-slave'))