Optionally add a default MOBILE request.

This enables persisting the mobile internet data connection, even
when Wi-Fi is enabled and serving as the default network (for faster
network switching).

Change-Id: I9d1512b3a8413c4f163c63d57e66bded017101e4
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index a7af838..7c3c11b 100644
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -6156,6 +6156,17 @@
         */
        public static final String MOBILE_DATA = "mobile_data";
 
+       /**
+        * Whether the mobile data connection should remain active even when higher
+        * priority networks like WiFi are active, to help make network switching faster.
+        *
+        * See ConnectivityService for more info.
+        *
+        * (0 = disabled, 1 = enabled)
+        * @hide
+        */
+       public static final String MOBILE_DATA_ALWAYS_ON = "mobile_data_always_on";
+
        /** {@hide} */
        public static final String NETSTATS_ENABLED = "netstats_enabled";
        /** {@hide} */