[Cros-SR Logging] Adds GetClient to AppListController interface

Adds GetClient() method to AppListController interface that enables
us to notify Chrome from Ash side.
E.g. AppListController::Get()->GetClient()->SomeAction()

Bug: 972817
Change-Id: I3205848e152943295f070c1dfec499b85f3616b6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1659664
Commit-Queue: Thanh Nguyen <thanhdng@chromium.org>
Reviewed-by: Jia Meng <jiameng@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#669556}
3 files changed