Improve Type @IntDef

Before CL: @IntDef was declaring COUNT inside @IntDef (as one of values) and this is different from other @IntDef (they use NUM_ENTRIES outside @IntDef)

After CL: COUNT/NUM_ENTRIES is removed at all because is not required at all

BUG=919666

Change-Id: I31eb7afffe7d95632142d0fbe2728dd7b590101e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1512635
Commit-Queue: Marcin Wiącek <marcin@mwiacek.com>
Reviewed-by: Friedrich [CET] <fhorschig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#639658}