GitLab

Following https://crrev.com/c/567940, this patch greatly simplifies the
interface to PermissionPrompt as follows:
- Object creation and showing a prompt are now tied. Move Show() and
  SetDelegate() logic into the ctor.
- Hiding only happens by object destruction. Remove HidesAutomatically()
  and move Hide() logic ino the dtor.

This patch also cleans up MockPermissionPrompt{,Factory} accordingly,
moving some logic previously from MockPermissionPrompt::Show() to the
factory.

Change-Id: I7868d645df6dbba8ea5706a8d9e7e59cfe1b157f
Reviewed-on: https://chromium-review.googlesource.com/572894
Commit-Queue: Timothy Loh <timloh@chromium.org>
Reviewed-by: Raymes Khoury <raymes@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487421}