GitLab

This CL:
1) Ports chrome/browser/bookmarks/managed_bookmark_service_factory.h/cc
to iOS
2) Updates bookmark_client_impl.h/cc with an instance of
ManagedBookmarkService, gotten from the factory.
3) Instantiates the new service where all browser state keyed service
factories are invoked.

Bug: 1065187
Change-Id: I840a3b2496310f0a3f40be20a35e6d71144dcdc8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2142106
Commit-Queue: edchin <edchin@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758134}