These macros mimic Chromium's histogram_macros.h, so we can use
similar values for our histograms.

BUG=angleproject:944
BUG=436191

Change-Id: If77abaf71964d26a6269183e51b68b76bb562085
Reviewed-on: https://chromium-review.googlesource.com/266523Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>