Fixed Linux bots to disable GPU otherwise process is terminated

tools/dartium/buildbot_annotated_steps.py

 #!/usr/bin/python
 
 # Copyright (c) 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.
 
 """Dartium buildbot steps
 
 Archive dartium, content_shell, and chromedriver to the cloud storage bucket
 gs://dart-archive, and run tests, including the Dart layout tests.
@@ skipping 16 matching lines @@
 
 # We limit testing on drt since it takes a long time to run.
 DRT_FILTER = 'html'
 
 def RunDartTests(mode, component, suite, arch, checked, test_filter=None,
                  is_win_ninja=False):
   """Runs tests using the Dart test.py or the layout test runner.
   """
   cmd = []
   if sys.platform.startswith('linux'):
-    cmd = ['xvfb-run', '-a']
+    cmd = ['xvfb-run', '--server-args=-screen 0 1024x768x24','-a']
   cmd.append(sys.executable)
   script = os.path.join(DART_PATH, 'tools', 'dartium', 'test.py')
   cmd.append(script)
   cmd.append('--buildbot')
   cmd.append('--mode=' + mode)
   cmd.append('--component=' + component)
   cmd.append('--suite=' + suite)
   cmd.append('--arch=' + arch)
   cmd.append('--' + checked)
   cmd.append('--no-show-results')
@@ skipping 68 matching lines @@
                   test_filter=DRT_FILTER) or result
     result = Test(info, 'drt', 'core', 'checked') or result
 
   # On the 'be' channel, we only archive to the latest bucket if all tests were
   # successful.
   if result == 0 and info.channel == 'be':
     result = upload_steps.ArchiveAndUpload(info, archive_latest=True) or result
 
 if __name__ == '__main__':
   sys.exit(main())