Layout aligned to dp grid for portrait (1/3)

This CL sets fixed dp values for the recents item views based off the UX
spec.  Vertical margins will be handled by an item decorator in the next
CL to handle special cases.

Bug: 131610834
Test: Builds
Change-Id: Ieb7936bd24933552844a6bd1bdb9e3101b8cdca4
4 files changed