Seen this here:
https://build.chromium.org/p/tryserver.chromium.android/builders/android_optional_gpu_tests_rel/builds/2967

+---------------------------------------------------------------------------+
| Shard 0  https://chromium-swarm.appspot.com/user/task/350768a382b20610    |
+---------------------------------------------------------------------------+
Additional test environment:
    CHROME_DEVEL_SANDBOX=/opt/chromium/chrome_sandbox
    LANG=en_US.UTF-8
Command: /usr/bin/python ../../testing/scripts/run_gpu_integration_test_as_googletest.py ../../content/test/gpu/run_gpu_integration_test.py pixel --show-stdout --browser=android-chromium -v --extra-browser-args=--enable-logging=stderr --js-flags=--expose-gc --refimg-cloud-storage-bucket chromium-gpu-archive/reference-images --os-type android --build-revision 19ae4d04c84aa9453c35e3aa8a470045a3f675d1 --test-machine-name android_optional_gpu_tests_rel --download-refimg-from-cloud-storage --isolated-script-test-output=/b/swarm_slave/w/io4Z5ntq/output.json --isolated-script-test-chartjson-output=/b/swarm_slave/w/io4Z5ntq/chartjson-output.json

(INFO) 2017-03-20 19:04:32,899 cmd_helper._ValidateAndLogCommand:161  [host]> /b/swarm_slave/w/irAMJkYT/third_party/catapult/devil/bin/deps/linux2/x86_64/bin/adb devices
(INFO) 2017-03-20 19:04:32,902 cmd_helper._ValidateAndLogCommand:161  [host]> /b/swarm_slave/w/irAMJkYT/third_party/catapult/devil/bin/deps/linux2/x86_64/bin/adb devices
(INFO) 2017-03-20 19:04:32,908 cmd_helper._ValidateAndLogCommand:161  [host]> /b/swarm_slave/w/irAMJkYT/third_party/catapult/devil/bin/deps/linux2/x86_64/bin/adb kill-server
(INFO) 2017-03-20 19:04:32,916 exception_formatter.PrintFormattedException:19  Try printing formatted exception: <type 'exceptions.AttributeError'> 'NoneType' object has no attribute 'platform' <traceback object at 0x7fa207de65a8>

Traceback (most recent call last):
  <module> at /b/swarm_slave/w/irAMJkYT/third_party/catapult/telemetry/telemetry/testing/run_browser_tests.py:354
    ret_code = RunTests(sys.argv[1:])
  RunTests at /b/swarm_slave/w/irAMJkYT/third_party/catapult/telemetry/telemetry/testing/run_browser_tests.py:322
    ret, _, _ = runner.run()
  run at /b/swarm_slave/w/irAMJkYT/third_party/catapult/third_party/typ/typ/runner.py:178
    ret, full_results = self._run_tests(result_set, test_set)
  _run_tests at /b/swarm_slave/w/irAMJkYT/third_party/catapult/third_party/typ/typ/runner.py:438
    self._run_one_set(self.stats, result_set, test_set)
  _run_one_set at /b/swarm_slave/w/irAMJkYT/third_party/catapult/third_party/typ/typ/runner.py:483
    test_set.isolated_tests, 1)
  _run_list at /b/swarm_slave/w/irAMJkYT/third_party/catapult/third_party/typ/typ/runner.py:509
    _setup_process, _teardown_process)
  make_pool at /b/swarm_slave/w/irAMJkYT/third_party/catapult/third_party/typ/typ/pool.py:28
    return _AsyncPool(host, jobs, callback, context, pre_fn, post_fn)
  __init__ at /b/swarm_slave/w/irAMJkYT/third_party/catapult/third_party/typ/typ/pool.py:188
    self.context_after_pre = pre_fn(self.host, 1, self.context)
  _setup_process at /b/swarm_slave/w/irAMJkYT/third_party/catapult/third_party/typ/typ/runner.py:776
    child.context_after_setup = child.setup_fn(child, child.context)
  _SetUpProcess at /b/swarm_slave/w/irAMJkYT/third_party/catapult/telemetry/telemetry/testing/run_browser_tests.py:344
    context.test_class.SetUpProcess()
  SetUpProcess at /b/swarm_slave/w/irAMJkYT/content/test/gpu/gpu_tests/pixel_integration_test.py:69
    cls.CustomizeBrowserArgs([])
  CustomizeBrowserArgs at /b/swarm_slave/w/irAMJkYT/content/test/gpu/gpu_tests/pixel_integration_test.py:86
    cls.SetBrowserOptions(cls._finder_options)
  SetBrowserOptions at /b/swarm_slave/w/irAMJkYT/third_party/catapult/telemetry/telemetry/testing/serially_executed_browser_test_case.py:72
    cls.platform = cls._browser_to_create.platform
AttributeError: 'NoneType' object has no attribute 'platform'

Locals:
  browser_options : [('android_blacklist_file', None), ('browser_executable', None), ('browser_options', [('_browser_startup_timeout', 60), ('_extra_browser_args', set(['--test-type=gpu', '--js-flags=--expose-gc', '--enable-logging=stderr', '--enable-gpu-benchmarking'])), ('browser_type', 'android-chromium'), ('browser_user_agent_type', None), ('clear_sytem_cache_for_browser_and_profile_on_start', False), ('disable_background_networking', True), ('disable_component_extensions_with_background_pages', True), ('disable_default ... ), ('positional_args', []), ('print_bootstrap_deps', None), ('profile_dir', None), ('profiler', None), ('reference_dir', '/b/swarm_slave/w/irAMJkYT/content/test/data/gpu/gpu_reference'), ('refimg_cloud_storage_bucket', 'chromium-gpu-archive/reference-images'), ('remote_platform_options', <telemetry.internal.platform.remote_platform_options.AndroidPlatformOptions object at 0x7fa207de2b10>), ('test_machine_name', 'android_optional_gpu_tests_rel'), ('upload_refimg_to_cloud_storage', False), ('verbosity', 1)] (truncated)
  cls             : <class 'gpu_tests.pixel_integration_test.PixelIntegrationTest'>

Running ['/usr/bin/python', '../../content/test/gpu/run_gpu_integration_test.py', 'pixel', '--show-stdout', '--browser=android-chromium', '-v', '--extra-browser-args=--enable-logging=stderr --js-flags=--expose-gc', '--refimg-cloud-storage-bucket', 'chromium-gpu-archive/reference-images', '--os-type', 'android', '--build-revision', '19ae4d04c84aa9453c35e3aa8a470045a3f675d1', '--test-machine-name', 'android_optional_gpu_tests_rel', '--download-refimg-from-cloud-storage', '--write-full-results-to', '/b/swarm_slave/w/io4Z5ntq/output.json'] in None (env: {'LOGNAME': 'chrome-bot', 'USER': 'chrome-bot', 'SWARMING_BOT_ID': 'build282-m4', 'BOTO_CONFIG': '/home/chrome-bot/.boto', 'PATH': '/sbin:/usr/sbin:/bin:/usr/bin:/opt/dell/srvadmin/bin', 'LANG': 'en_US.UTF-8', 'TERM': 'linux', 'SHELL': '/bin/bash', 'SWARMING_SERVER': 'https://chromium-swarm.appspot.com', 'SHLVL': '1', 'CHROME_DEVEL_SANDBOX': '/opt/chromium/chrome_sandbox', 'SWARMING_HEADLESS': '1', '_': '/usr/bin/python', 'SUDO_USER': 'root', 'HOME': '/home/chrome-bot', 'USERNAME': 'chrome-bot', 'SUDO_UID': '0', 'SWARMING_TASK_ID': '350768a382b20611', 'NO_GCE_CHECK': 'False', 'TMPDIR': '/b/swarm_slave/w/itxmrZsx', 'SUDO_COMMAND': '/bin/bash -c python /b/swarm_slave/swarming_bot.zip start_bot', 'SUDO_GID': '0', 'PWD': '/home/chrome-bot', 'MAIL': '/var/mail/chrome-bot'})
Command ['/usr/bin/python', '../../content/test/gpu/run_gpu_integration_test.py', 'pixel', '--show-stdout', '--browser=android-chromium', '-v', '--extra-browser-args=--enable-logging=stderr --js-flags=--expose-gc', '--refimg-cloud-storage-bucket', 'chromium-gpu-archive/reference-images', '--os-type', 'android', '--build-revision', '19ae4d04c84aa9453c35e3aa8a470045a3f675d1', '--test-machine-name', 'android_optional_gpu_tests_rel', '--download-refimg-from-cloud-storage', '--write-full-results-to', '/b/swarm_slave/w/io4Z5ntq/output.json'] returned exit code 1
+---------------------------------------------------------------------------+
| End of shard 0  Pending: 8.1s  Duration: 95.2s  Bot: build282-m4  Exit: 1 |
+---------------------------------------------------------------------------+
Total duration: 95.2s
step returned non-zero exit code: 1