SuperSize: Analyze on-demand DFMs

Stores onDemand status in metadata.
Updating the UI to be able to filter out on-demand modules is future
work.

Bug: 1171293
Change-Id: I57d23885825e6aa79dc865012058771f1a50cadd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2652928


Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Clark DuVall <cduvall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#848174}