GitLab

Add SharingMessageBridge without wiring it. The bridge does not store any
data on persistent storage.

Bug: 1034930
Change-Id: I0b19a136a2cc8a3e9ec11b7c1bb0f0b629996e52
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2002524Reviewed-by: Alex Chau <alexchau@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: vitaliii <vitaliii@chromium.org>
Commit-Queue: Rushan Suleymanov <rushans@google.com>
Cr-Commit-Position: refs/heads/master@{#733594}