Current chrome stable has a high number of crashes due to bugs in
this feature. These bugs are already fixed but the fixes are hard
to merge back. Therefore we decided to disable the feature in stable.
This CL is intended to be merged to stable and then reverted in tot.

Bug: chromium:762020
Change-Id: Ibd5a08e3b303a204fb84a408271a1c0f97cc5b7b
Reviewed-on: https://chromium-review.googlesource.com/738176Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48931}