Move Documents action bar update even later.

At some point Activity started restoring the Toolbar/ActionBar title
during onPostCreate(), which would clobber some of the setup we just
finished doing.  To fix, move our update to be even later in the
restore lifecycle.

Also fix grid item widths for small screen devices.

Bug: 17428127
Change-Id: I258121b6a6eec5924f92b02290a67d3ae7dd9cf6