This feature seems to be unused, and removing it will
simplify handling hooks a little bit.

Bug: 661382
Change-Id: I89f28dedb7f59cd475b176cfb1f023094520d6b7
Reviewed-on: https://chromium-review.googlesource.com/509614Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Paweł Hajdan Jr. <phajdan.jr@chromium.org>