Given that users may run into the issue described in  issue 452686 , it'd be better to enable mist for all existing targets under USE=mist, and explicitly set USE=-mist on the following conditions:

  overlay-lakitu
  overlay-jetstream-private
  overlay-marble-private
  project-termina
  features/minimum
  USE=cros_embedded

vapier, does it make sense?

if you add USE=mist to:
  profiles/targets/chromeos/make.defaults

and add USE=-mist to:
  profiles/features/embedded/make.defaults
  profiles/features/minimal/make.defaults

that should cover things.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/99ed9577aaeaaadbcd5645d3dae02f0eb0e130cc

commit 99ed9577aaeaaadbcd5645d3dae02f0eb0e130cc
Author: Ben Chan <benchan@chromium.org>
Date: Wed Nov 22 05:36:15 2017

profiles: enable 'mist' in chromeos, but not in minimal and embedded

chromeos-base/mist is now guarded under its own 'mist' use flag, instead
of the 'cellular' use flag. This CL enables 'mist' use flag in the
chromeos profile, but disable it in the minimal and embedded profiles to
keep things small.

BUG= chromium:787313 
TEST=`equery-$BOARD u target-chromium-os` includes mist.
TEST=Run remote trybots.

Change-Id: I67af4ed71aecc85ad38509d4d291e644571602bd
Reviewed-on: https://chromium-review.googlesource.com/782653
Commit-Ready: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

[modify] https://crrev.com/99ed9577aaeaaadbcd5645d3dae02f0eb0e130cc/profiles/features/minimal/make.defaults
[modify] https://crrev.com/99ed9577aaeaaadbcd5645d3dae02f0eb0e130cc/profiles/targets/chromeos/make.defaults
[modify] https://crrev.com/99ed9577aaeaaadbcd5645d3dae02f0eb0e130cc/profiles/features/embedded/make.defaults

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/692121478ff8776c02db8d7eef5db637d2e58601

commit 692121478ff8776c02db8d7eef5db637d2e58601
Author: Ben Chan <benchan@chromium.org>
Date: Wed Nov 22 05:36:15 2017

target-chromium-os: move mist under its own mist use flag

mist was used solely for switching cellular dongles from USB mass
storage mode into modem mode, but is now used for switching Ethernet
adapters from USB mass storage mode into Ethernet mode as well
(chromium:452686, CL:770295, CL:770298). This CL moves
chromeos-base/mist under its own 'mist' use flag to better reflect the
conditions that it may be used.

BUG= chromium:787313 
TEST=`equery-$BOARD g target-chromium-os` still includes mist.
TEST=Run remote trybots.

Change-Id: Ib325b940f3194e701779b8f2f9ad9a5cce54e4e4
Reviewed-on: https://chromium-review.googlesource.com/782654
Commit-Ready: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

[rename] https://crrev.com/692121478ff8776c02db8d7eef5db637d2e58601/virtual/target-chromium-os/target-chromium-os-1-r83.ebuild
[modify] https://crrev.com/692121478ff8776c02db8d7eef5db637d2e58601/virtual/target-chromium-os/target-chromium-os-1.ebuild