telemetry_unittests seems failed due to accessing a file from multiple processes.
https://chromium-swarm.appspot.com/task?id=37d92084c575b410&refresh=10&show_raw=1

The root error might be the following one: 

  WindowsError: [Error 32] The process cannot access the file because it is being used by another process: 'e:\\b\\swarm_slave\\w\\itqlje7p\\tmpanbxte'

Could you take a look?
This is the log of the failure. 

====
[566/567] telemetry.web_perf.timeline_based_page_test_unittest.TimelineBasedPageTestTest.testTraceCaptureUponFailure queued
[567/567] telemetry.web_perf.timeline_based_page_test_unittest.TimelineBasedPageTestTest.testTraceCaptureUponFailure passed 12.1130s:
  Closing browser (pid=2744) ...
  Successfully shut down browser cooperatively
  Browser is closed.
  Chrome build location for win_AMD64 not found. Browser will be run without Flash.
  Tsproxy commandline: ['e:\\b\\depot_tools\\python276_bin\\python.exe', 'e:\\b\\swarm_slave\\w\\ir\\third_party\\catapult\\telemetry\\third_party\\tsproxy\\tsproxy.py', '--port=0', '--desthost=127.0.0.1']
  TsProxy port: 59024
  Trace config file string: {"trace_config": {"included_categories": ["toplevel", "trace_event_overhead", "benchmark", "blink.console", "webkit.console"], "record_mode": "record-as-much-as-possible"}}
  Requested remote debugging port: 0
  Starting Chrome ['../../out\\Release_x64\\chrome.exe', '--enable-net-benchmarking', '--metrics-recording-only', '--no-default-browser-check', '--no-first-run', '--enable-gpu-benchmarking', '--disable-background-networking', '--proxy-server=socks://localhost:59024', '--ignore-certificate-errors', '--disable-component-extensions-with-background-pages', '--disable-default-apps', '--disable-search-geolocation-disclosure', '--remote-debugging-port=0', '--enable-crash-reporter-for-testing', '--disable-component-update', '--window-size=1280,1024', '--user-data-dir=e:\\b\\swarm_slave\\w\\itqlje7p\\tmpe0txfq', '--trace-config-file=e:\\b\\swarm_slave\\w\\itqlje7p\\tmpvonprz\\chrome-trace-config.json', 'about:blank']
  Discovered ephemeral port 59026
  Browser target: /devtools/browser/154d0976-e66d-4c53-bd60-212a596a7730
  Browser started (pid=6112).
  OS: win win7
  Detailed OS version: 6.1.7601
  Browser command line: "../../out\Release_x64\chrome.exe" --enable-net-benchmarking --metrics-recording-only --no-default-browser-check --no-first-run --enable-gpu-benchmarking --disable-background-networking --proxy-server=socks://localhost:59024 --ignore-certificate-errors --disable-component-extensions-with-background-pages --disable-default-apps --disable-search-geolocation-disclosure --remote-debugging-port=0 --enable-crash-reporter-for-testing --disable-component-update --window-size=1280,1024 --user-data-dir="e:\b\swarm_slave\w\itqlje7p\tmpe0txfq" --trace-config-file="e:\b\swarm_slave\w\itqlje7p\tmpvonprz\chrome-trace-config.json" --flag-switches-begin --flag-switches-end about:blank
  GPU device 0: VENDOR = 0x15ad, DEVICE = 0x405
  GPU Attributes:
    amd_switchable      : False
    basic_info_state    : 1
    can_support_threaded_texture_mailbox: False
    context_info_state  : 1
    direct_rendering    : True
    driver_date         : 2017/04/07
    driver_vendor       : Google Inc.
    driver_version      : 3.3.0.2
    dx_diagnostics_info_state: 3
    gl_extensions       : 
    gl_renderer         : Google SwiftShader
    gl_reset_notification_strategy: 0
    gl_vendor           : Google Inc.
    gl_version          : OpenGL ES 2.0 SwiftShader
    gl_ws_extensions    : 
    gl_ws_vendor        : 
    gl_ws_version       : 
    hdr                 : False
    in_process_gpu      : True
    initialization_time : 0
    jpeg_decode_accelerator_supported: False
    max_msaa_samples    : 4
    optimus             : False
    passthrough_cmd_decoder: False
    pixel_shader_version: 3.0
    process_crash_count : 1
    sandboxed           : False
    software_rendering  : True
    supports_overlays   : False
    vertex_shader_version: 3.0
    video_decode_accelerator_flags: 0
  Feature Status:
    2d_canvas           : unavailable_software
    checker_imaging     : enabled_on
    flash_3d            : unavailable_software
    flash_stage3d       : unavailable_software
    flash_stage3d_baseline: unavailable_software
    gpu_compositing     : unavailable_software
    multiple_raster_threads: enabled_on
    native_gpu_memory_buffers: disabled_software
    rasterization       : unavailable_software
    video_decode        : unavailable_software
    video_encode        : unavailable_software
    webgl               : enabled_readback
    webgl2              : unavailable_off
  Driver Bug Workarounds:
    clear_uniforms_before_first_program_use
    decode_encode_srgb_for_generatemipmap
    disable_accelerated_vpx_decode
    disable_direct_composition
    disable_discard_framebuffer
    disable_dxgi_zero_copy_video
    disable_framebuffer_cmaa
    exit_on_context_lost
    scalarize_vec_and_mat_constructor_args
  Issuing command to ts_proxy_server: set rtt 0
  Issuing command to ts_proxy_server: set inkbps 0
  Issuing command to ts_proxy_server: set outkbps 0
  PageCacheTemperature: any
  *************** BROWSER STANDARD OUTPUT ***************
  
  *********** END OF BROWSER STANDARD OUTPUT ************
  ********************* BROWSER LOG *********************
  No log file
  ***************** END OF BROWSER LOG ******************
  Taking screenshots upon failures disabled.
  Chrome version: 3180
  Error when deleting e:\b\swarm_slave\w\itqlje7p\tmpanbxte, will try again at exit.
  Traceback (most recent call last):
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_controller_backend.py", line 289, in CollectAgentTraceData
      os.remove(self._trace_log)
  WindowsError: [Error 32] The process cannot access the file because it is being used by another process: 'e:\\b\\swarm_slave\\w\\itqlje7p\\tmpanbxte'
  Trace sizes in bytes: {'traceEvents': 1107423L, 'telemetry': 34748L, 'tabIds': 40L}
  Closing browser (pid=6112) ...
  Successfully shut down browser cooperatively
  Browser is closed.

Retrying failed tests (attempt #1 of 3)...

ERROR:

Description = ERROR:

Description = [1/5] telemetry.internal.platform.tracing_agent.cpu_tracing_agent_unittest.CpuTracingAgentTest.testCollectAgentTraceData failed unexpectedly 0.8130s:
  Error when running wmic command, which gave output: 
  Error when running wmic command, which gave output: 
  Traceback (most recent call last):
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent_unittest.py", line 97, in testCollectAgentTraceData
      self._agent.StartAgentTracing(self._config, 0)
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 289, in StartAgentTracing
      self._KeepTakingSnapshots()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 298, in _KeepTakingSnapshots
      (self._collector.GetProcesses(), trace_time.Now()))
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 119, in GetProcesses
      processes = super(WindowsProcessCollector, self).GetProcesses()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 69, in GetProcesses
      self._ParseProcessString(proc_string) for proc_string in proc_strings
  TypeError: 'NoneType' object is not iterable
ERROR:

Description = ERROR:

Description = [2/5] telemetry.internal.platform.tracing_agent.cpu_tracing_agent_unittest.CpuTracingAgentTest.testCollectAgentTraceDataFormat failed unexpectedly 0.7580s:
  Error when running wmic command, which gave output: 
  Error when running wmic command, which gave output: 
  Traceback (most recent call last):
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent_unittest.py", line 107, in testCollectAgentTraceDataFormat
      self._agent.StartAgentTracing(self._config, 0)
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 289, in StartAgentTracing
      self._KeepTakingSnapshots()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 298, in _KeepTakingSnapshots
      (self._collector.GetProcesses(), trace_time.Now()))
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 119, in GetProcesses
      processes = super(WindowsProcessCollector, self).GetProcesses()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 69, in GetProcesses
      self._ParseProcessString(proc_string) for proc_string in proc_strings
  TypeError: 'NoneType' object is not iterable
ERROR:

Description = ERROR:

Description = [3/5] telemetry.internal.platform.tracing_agent.cpu_tracing_agent_unittest.CpuTracingAgentTest.testStartAgentTracing failed unexpectedly 0.7580s:
  Error when running wmic command, which gave output: 
  Error when running wmic command, which gave output: 
  Traceback (most recent call last):
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent_unittest.py", line 61, in testStartAgentTracing
      self.assertTrue(self._agent.StartAgentTracing(self._config, 0))
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 289, in StartAgentTracing
      self._KeepTakingSnapshots()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 298, in _KeepTakingSnapshots
      (self._collector.GetProcesses(), trace_time.Now()))
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 119, in GetProcesses
      processes = super(WindowsProcessCollector, self).GetProcesses()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 69, in GetProcesses
      self._ParseProcessString(proc_string) for proc_string in proc_strings
  TypeError: 'NoneType' object is not iterable
ERROR:

Description = ERROR:

Description = [4/5] telemetry.internal.platform.tracing_agent.cpu_tracing_agent_unittest.CpuTracingAgentTest.testStopAgentTracing failed unexpectedly 1.7700s:
  Error when running wmic command, which gave output: 
  Error when running wmic command, which gave output: 
  Traceback (most recent call last):
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent_unittest.py", line 83, in testStopAgentTracing
      self._agent.StartAgentTracing(self._config, 0)
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 289, in StartAgentTracing
      self._KeepTakingSnapshots()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 298, in _KeepTakingSnapshots
      (self._collector.GetProcesses(), trace_time.Now()))
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 119, in GetProcesses
      processes = super(WindowsProcessCollector, self).GetProcesses()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 69, in GetProcesses
      self._ParseProcessString(proc_string) for proc_string in proc_strings
  TypeError: 'NoneType' object is not iterable
ERROR:

Description = ERROR:

Description = [5/5] telemetry.internal.platform.tracing_agent.cpu_tracing_agent_unittest.CpuTracingAgentTest.testTraceSpecifiesTelemetryClockDomain failed unexpectedly 0.8200s:
  Error when running wmic command, which gave output: 
  Error when running wmic command, which gave output: 
  Traceback (most recent call last):
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent_unittest.py", line 143, in testTraceSpecifiesTelemetryClockDomain
      self._agent.StartAgentTracing(self._config, 0)
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 289, in StartAgentTracing
      self._KeepTakingSnapshots()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 298, in _KeepTakingSnapshots
      (self._collector.GetProcesses(), trace_time.Now()))
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 119, in GetProcesses
      processes = super(WindowsProcessCollector, self).GetProcesses()
    File "e:\b\swarm_slave\w\ir\third_party\catapult\telemetry\telemetry\internal\platform\tracing_agent\cpu_tracing_agent.py", line 69, in GetProcesses
      self._ParseProcessString(proc_string) for proc_string in proc_strings
  TypeError: 'NoneType' object is not iterable