Revert "Handle KEYCODE_SOFT_SLEEP from Ungaze."

This reverts commit 677adf1e66ba83b8fb2c849c181303b35bd489bc.

Hiding new keycode to prevent change to public API before resubmitting.

Change-Id: Ic43273dd0c7ade1d51a36b77f363543f1df466e8
7 files changed