never mind, apparently it is "use_vs_code_analysis" and was added in https://codereview.chromium.org/1658903002/ .

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/de9261d3072db949f60ffcaf09df404cfd7b807f

commit de9261d3072db949f60ffcaf09df404cfd7b807f
Author: dpranke <dpranke@chromium.org>
Date: Wed Mar 23 21:43:21 2016

Add MB support for the windows analyze bot.

This adds the MB config for the 'Chromium Windows Analyze' bot
on the chromium.fyi waterfall, and adds the needed flag maps
to disable precompiled headers (incl. adding a disable_precompiled_headers
flag to GN) and adding 'win_analyze' mixin (we need to actually
implement the win_analyze GN flag still, though).

R=brettw@chromium.org, brucedawson@chromium.org
BUG= 597112 

Review URL: https://codereview.chromium.org/1827683002

Cr-Commit-Position: refs/heads/master@{#382931}

[modify] https://crrev.com/de9261d3072db949f60ffcaf09df404cfd7b807f/build/config/BUILD.gn
[modify] https://crrev.com/de9261d3072db949f60ffcaf09df404cfd7b807f/tools/mb/mb_config.pyl

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build.git/+/a586de1824aadd55ae2642a911f592a80936ec0e

commit a586de1824aadd55ae2642a911f592a80936ec0e
Author: dpranke@chromium.org <dpranke@chromium.org>
Date: Wed Mar 23 22:07:27 2016

Switch the Chromium Windows Analyze bot to MB.

R=brucedawson@chromium.org
BUG= 597112 

Review URL: https://codereview.chromium.org/1821003005

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/build@299452 0039d316-1c4b-4281-b951-d872f2087c98

[modify] https://crrev.com/a586de1824aadd55ae2642a911f592a80936ec0e/scripts/slave/recipes/win_analyze.expected/full_chromium_fyi_Chromium_Windows_Analyze.json
[modify] https://crrev.com/a586de1824aadd55ae2642a911f592a80936ec0e/scripts/slave/recipes/win_analyze.py

The MB bot is behaving correctly and producing good results - three clean builds produced so far.