This is necessary to be able to share the data for read-only
objects amongst multiple broker instances.

Bug: v8:7790
Change-Id: I0da58f8a9eded06ac6e994bc540a3a1bc481d6a7
Reviewed-on: https://chromium-review.googlesource.com/1251308Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56292}