Merge "Introduce zen mode."

        public static final String LOCK_SCREEN_SHOW_NOTIFICATIONS =

                "lock_screen_show_notifications";

        /**

         * Defines global zen mode.  One of ZEN_MODE_OFF, ZEN_MODE_LIMITED, ZEN_MODE_FULL.

         *

         * @hide

         */

        public static final String ZEN_MODE = "zen_mode";

        /** @hide */ public static final int ZEN_MODE_OFF = 0;

        /** @hide */ public static final int ZEN_MODE_LIMITED = 1;

        /** @hide */ public static final int ZEN_MODE_FULL = 2;

        /** @hide */ public static String zenModeToString(int mode) {

            if (mode == ZEN_MODE_OFF) return "ZEN_MODE_OFF";

            if (mode == ZEN_MODE_LIMITED) return "ZEN_MODE_LIMITED";

            if (mode == ZEN_MODE_FULL) return "ZEN_MODE_FULL";

            throw new IllegalArgumentException("Invalid zen mode: " + mode);

        }

        /**

         * Settings to backup. This is here so that it's in the same place as the settings

         * keys and easy to update.