This forces us to not use exceptions when they aren't enabled.

Change-Id: I6abaf08ca4c275bd2fa0625905fd1de3448237ce
Reviewed-on: https://chromium-review.googlesource.com/250901Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>