Related to wanting to make the previews component no longer be layered for ios ( bug 778292 ), a baby step would be to move PreviewsIOData and PreviewsUIService from core/ to content/.
I believe this minimal step would be sufficient to enable the cacao project to have previews be able to depend on the new optimization_guide component to get notified of updates.
Comment 1 by bengr@chromium.org
, Nov 3 2017