Enable lucid sleep (wake on wi-fi SSID) and add to Privacy options.
* Change the wake on wifi pref to a boolean. Eventually we will need to worry about packets, but for now having an integer pref makes things too complicated, partially because if/when we do add the packets feature, we don't want to overwrite user settings.
* Make the WakeOnWifiFeatures enum bitfield-like for easier setting of the options now and in the future.
* Set the pref to enabled by default.
* Add the --disable-wake-on-wifi kill switch to WakeOnWifiManager.
* --wake-on-packet still works unless --disable-wake-on-wifi is also specified.
BUG=424719
R=stevenjb@chromium.org,asvitkine@chromium.org
CC=dbeam@chromium.org
TBR=asvitkine@chromium.org
# asvitkine OOO, but this complies with his past reviews
Review URL: https://codereview.chromium.org/
811973002
Cr-Commit-Position: refs/heads/master@{#309576}