Use uint16 for port numbers, content/ edition

Use uint16 for port numbers, content/ edition

This is a piece of a larger CL, split up to avoid overwhelming reviewers. The
entire CL can be viewed at https://codereview.chromium.org/655063002/ .
The intent is to get each piece reviewed separately, then finally land the large
CL after all parts have been approved.

BUG=81439
TEST=none

[Peter Kasting, 2014-11-12 23:50:12]

pkasting@chromium.org changed reviewers:
+ davidben@chromium.org

[Peter Kasting, 2014-11-12 23:54:20]

This is not an independent CL; please see the description for a link to the full
context including brief rationale.

To minimize the chance of problems, after getting green try runs on the large
change, I manually reviewed each smaller CL and added comments where helpful. 
(This particular CL had no places needing explanation.)

[davidben, 2014-11-13 19:17:38]

lgtm