The error message is:
  ** Presubmit ERRORS **
  Validating story expectation data failed.
  ***************
  Running all tests in /b/swarming/w/ir/cache/builder/chromium_presubmit/src/third_party/blink/perf_tests
  ERROR:root:Story worker-structured-clone-json-serialize.html is not in the story set.
  Traceback (most recent call last):
    <module> at /b/swarming/w/ir/cache/builder/chromium_presubmit/src/tools/perf/validate_story_expectation_data:12
      sys.exit(story_expectation_validator.main(sys.argv[1:]))
    main at /b/swarming/w/ir/cache/builder/chromium_presubmit/src/tools/perf/core/story_expectation_validator.py:80
      validate_story_names(benchmarks, raw_expectations_data)
    validate_story_names at /b/swarming/w/ir/cache/builder/chromium_presubmit/src/tools/perf/core/story_expectation_validator.py:35
      assert not failed_stories, 'Incorrect story names: %s' % str(failed_stories)
  AssertionError: Incorrect story names: ['worker-structured-clone-json-serialize.html']
  Locals:
    b                     : <benchmarks.blink_perf.BlinkPerfBindings object at 0x7fc4fd714510>
    benchmark             : <class 'benchmarks.blink_perf.BlinkPerfBindings'>
    benchmarks            : [<class 'contrib.cluster_telemetry.analysis_metrics_ct.AnalysisMetricsCT'>, <class 'contrib.blink_perf_cmdline.blink_perf_cmdline.BlinkPerfAll'>, <class 'benchmarks.blink_perf.BlinkPerfAccessibility'>, <class 'benchmarks.blink_perf.BlinkPerfBindings'>, <class 'benchmarks.blink_perf.BlinkPerfCanvas'>, <class 'benchmarks.blink_perf.BlinkPerfCSS'>, <class 'benchmarks.blink_perf.BlinkPerfDOM'>, <class 'benchmarks.blink_perf.BlinkPerfEvents'>, <class 'benchmarks.blink_perf.BlinkPerfImageDecoder'>, <class 'ben ... .Wasm'>, <class 'benchmarks.webrtc.WebrtcPerfBenchmark'>, <class 'contrib.vr_benchmarks.vr_benchmarks.XrBrowsingStatic'>, <class 'contrib.vr_benchmarks.vr_benchmarks.XrBrowsingWprSmoothness'>, <class 'contrib.vr_benchmarks.vr_benchmarks.XrBrowsingWprStatic'>, <class 'contrib.vr_benchmarks.vr_benchmarks.XrWebVrLiveStatic'>, <class 'contrib.vr_benchmarks.vr_benchmarks.XrWebVrStatic'>, <class 'contrib.vr_benchmarks.vr_benchmarks.XrWebVrWprStatic'>, <class 'contrib.vr_benchmarks.vr_benchmarks.XrWebXrStatic'>] (truncated)
    failed_stories        : ['worker-structured-clone-json-serialize.html']
    raw_expectations_data : '# Test Expectation file for telemetry tests.\n# Instructions of how to use this file:\n# https://chromium.googlesource.com/chromium/src/+/master/docs/speed/bot_health_sheriffing/how_to_disable_a_story.md\n\n# tags: All Android_Go Android_One Android_Svelte Android_Low_End\n# tags: Android_Webview Android_but_not_webview Mac Win Linux\n# tags: ChromeOS Android Desktop Nexus_5 Nexus_5X Nexus_6P\n# tags: Nexus_7 Mac_10.11 Mac_10.12 Nexus6_Webview Nexus5X_Webview\n# tags: Pixel_2 Win_7 Win_10\n\n# Benchmark ... Linux ] loading.desktop.network_service/Taobao_cold [ Skip ]\ncrbug.com/853835 [ Linux ] loading.desktop.network_service/Taobao_warm [ Skip ]\ncrbug.com/879833 [ Linux ] loading.desktop.network_service/Walgreens_cold [ Skip ]\ncrbug.com/879833 [ Linux ] loading.desktop.network_service/Walgreens_warm [ Skip ]\n\n# Benchmark: loading.desktop_layout_ng\ncrbug.com/879833 [ Linux ] loading.desktop_layout_ng/Walgreens_cold [ Skip ]\ncrbug.com/879833 [ Linux ] loading.desktop_layout_ng/Walgreens_warm [ Skip ]\n' (truncated)
    story_set             : <telemetry.story.story_set.StorySet object at 0x7fc4fd59eb10>
  ***************
  Presubmit checks took 25.8s to calculate.
  step returned non-zero exit code: 1