Debug registers are currently initialized to 0 until methods are added
to ThreadInfo to collect them.
Bug: crashpad:30
Change-Id: Ic1aab1151dcd4bed48eca8a60b76fb0d8d613418
Reviewed-on: https://chromium-review.googlesource.com/579889
Reviewed-by: Mark Mentovai <mark@chromium.org>