Reformat and update comments

Reformat to 100 columns.  Use indentation, especially for switch
statements, that matches current coding style.

Update some obsolete comments.

Break a single-line if-statement into 3 lines.

No substantive code changes.

This was requested during review of previous CL for b/21282652, but
factored out into a separate CL.

Change-Id: Id5f319ff2226703b413fb08f265677ce7d4dd205