This happens before and after the refactor. Splitting out from  bug 663911  which seems to have an unrelated issue which was resolved.

https://build.chromium.org/p/tryserver.chromium.perf/builders/winx64_zen_perf_bisect/builds/586
https://build.chromium.org/p/tryserver.chromium.perf/builders/win_perf_bisect/builds/7044

In both of these bisect, the test runs green all 5 runs with Captured Output that looks like this:
https://build.chromium.org/p/tryserver.chromium.perf/builders/win_perf_bisect/builds/7044/steps/Gathering%20reference%20values.Performance%20Test%201%20of%205/logs/Captured%20Output
C:\b\depot_tools\python276_bin\python.exe C:\b\rr\tmpjac2pr\rw\checkout\scripts\slave\runisolatedtest.py --test_name "" --builder_name win_perf_bisect --checkout_dir C:\b\c\b\win_perf_bisect C:\b\c\b\win_perf_bisect\src\tools\perf\run_benchmark -- C:\b\depot_tools\python276_bin\python.exe C:\b\c\b\win_perf_bisect\src\tools\perf\run_benchmark -v --browser=release --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests startup.warm.blank_page --output-dir=C:\b\rr\tmpjac2pr\w\bisect_results\5e346441-ebb1-4b40-92b8-7c0bd6235088
...
[ RUN      ] blank_page.html
...
[       OK ] blank_page.html (10229 ms)
INFO:root:Successfully shut down browser cooperatively
[  PASSED  ] 1 test.


Then the chartjson it generates has no values:
https://build.chromium.org/p/tryserver.chromium.perf/builders/win_perf_bisect/builds/7044/steps/Gathering%20reference%20values.Reading%20chartjson%20results/logs/json.output
{
  "benchmark_description": "Measures warm startup time with a clean profile.", 
  "benchmark_metadata": {
    "description": "Measures warm startup time with a clean profile.", 
    "name": "startup.warm.blank_page", 
    "rerun_options": [], 
    "type": "telemetry_benchmark"
  }, 
  "benchmark_name": "startup.warm.blank_page", 
  "charts": {}, 
  "enabled": true, 
  "format_version": "0.1", 
  "next_version": "0.2", 
  "trace_rerun_options": []
}

There is no --story-filter passed in on the command line, so it's unlikely to be related to the work there.

The startup benchmark on Windows is unowned, so not sure what do do here. Nat, help?