GitLab

sync_listen_notifications istn't used neither in production code,
nor in tests. Hence removing.

Bug: 880056, 801985
Change-Id: If518c9dad72b3f718ee649844a6cf3a4703bc0c7
Reviewed-on: https://chromium-review.googlesource.com/c/1307434
Commit-Queue: Tatiana Gornak <melandory@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607209}