Remove (already-hidden) global fullscreen / mouselock settings.

This UI was already hidden. This just removes the HTML code for those
radio buttons, as well as the unused code for showing these buttons, and
the strings.

BUG=610900
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2045163002
Cr-Commit-Position: refs/heads/master@{#398757}
4 files changed