As of crrev.com/c/1129547 the perf team is no longer maintaining the build side upload scripts and they should be removed:

scripts/slave/results_dashboard.py
scripts/slave/upload_perf_dashboard_results.py

Please instead use the src side scripts in src/tools/perf

There is still at least one known use case of these scripts, webrtc:
https://cs.chromium.org/chromium/build/scripts/slave/recipe_modules/webrtc/steps.py?q=_output_perf_results_if_present&sq=package:chromium&dr=CSs&l=314

After the webrtc case is gone, we can also remove the swarming api that is specific to perf output.  I will file a separate bug for the webrtc and swarming use case.