Bundle MEI preload data as a component and include a default
version of that component with Chrome. The component
updater is behind the PreloadMediaEngagementData feature
flag.

BUG=787464

Change-Id: Icfc07296caf48e663c9ed7de864f3a1ae6a513d0
Reviewed-on: https://chromium-review.googlesource.com/784892
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Reviewed-by: Michael Moss <mmoss@chromium.org>
Reviewed-by: Greg Thompson <grt@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523760}