The place to inject would be at around https://cs.chromium.org/chromium/infra/luci/appengine/swarming/swarming_bot/bot_code/bot_main.py?l=813

which is far enough that the bot is not completely hosed but before requesting tasks from the server.

Greg if you have time today you can take it otherwise this will have to wait to tomorrow.

I'm trying something like this in the test itself in https://chromium-review.googlesource.com/c/chromium/src/+/771330. I haven't yet hit a bot with the problem, but I'm continuing to rerun the tests on win7_chromium_rel_ng hoping for a jackpot.

Jackpot! https://chromium-swarm.appspot.com/task?id=39d8301768c43510&refresh=10&show_raw=1:

[1115/030957.388:ERROR:always_on_top_window_killer_win.cc(251)] There is an always on top window on the desktop. This may have been caused by a previous test and may cause this test to fail; window class name: VMwareDragDetWndClass; owning process lineage: (process_id: 2068, command_line: ""C:\Program Files\VMware\VMware Tools\vmtoolsd.exe" -n vmusr"), (process_id: 1692, command_line: "C:\Windows\Explorer.EXE"); screen snapshot saved to file: "e:\b\swarm_slave\w\io867l_p\ss_20171115030957_327.png";
[1115/030957.389:ERROR:always_on_top_window_killer_win.cc(258)] Stripped WS_EX_TOPMOST.
[1115/030957.641:ERROR:always_on_top_window_killer_win.cc(263)] Minimized window.

Sending out for review now.

This is no longer blocking, as the test itself now takes care of it. It may still be a nice-to-have, but I'll leave it to you infra folks to prioritize it as you see fit.

Will take it on.