This only seems to affect GCC's enum-compare warning,
because we were comparing an untyped enum with a size_t enum.

BUG=None 

Change-Id: I74b8315cff61344d1b7700b1c56a40d2ffce41e2
Reviewed-on: https://chromium-review.googlesource.com/698296Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>