This separate the layouts for the message list item so that we can
change the phone and tablet independently.
The visuals weren't really updated except for easy to win padding
reductions.
Change-Id: I92ed6e1bf275551abd77fd788b5c7ac22f639843
This is a cherry-pick of f872876699 :
- Use new recommended sw600dp instead of w600dp to avoid having the
"personality" change on configuration change
- remove the use of xlarge/large for specializing values since the
framework team discourages any use of the buckets (and have also changed
the ordering so that they take lower priority)
Change-Id: I645bfb7cddcda8b53569af927f6fa23180e73e1f