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This CL moves the data store and store client from bookmarks into cr.ui
and makes them generic so that they can be used by other pages.

Bug: 906508
Change-Id: I578a3e0b308b1d21ad412cf8be7e08db3b402469
Reviewed-on: https://chromium-review.googlesource.com/c/1369444
Commit-Queue: Reka Norman <rekanorman@google.com>
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: calamity <calamity@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616101}