DevTools: WebSocketFrameView: use sortable data grid.

This is a preparation step. After viewport data grid is introduced, we
could easily enable "auto-update".

Also fixed minor glitches and added js-docs.

BUG=

Review URL: https://codereview.chromium.org/426093006

git-svn-id: svn://svn.chromium.org/blink/trunk@179248 bbb929c8-8fbe-4397-9dbb-9b2b20218538