OomIntervention opt-out should work properly with 'show original'

OomIntervention should not be re-triggered on the same page if the user declines the intervention once.
This CL fixes the bug.

Bug: 889131, 887119
Change-Id: Idb9eebb2bb9f79756b63f0e010fe018ba5c490e8
Reviewed-on: https://chromium-review.googlesource.com/1245019
Commit-Queue: Yuzu Saijo <yuzus@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594574}
OomInterventionImpl::~OomInterventionImpl() {}

OomInterventionImpl::~OomInterventionImpl() {}
