Add mobile data on/off switch.

bug:2251458
diff --git a/core/java/android/net/IConnectivityManager.aidl b/core/java/android/net/IConnectivityManager.aidl
index 508e9c3a..2514693 100644
--- a/core/java/android/net/IConnectivityManager.aidl
+++ b/core/java/android/net/IConnectivityManager.aidl
@@ -51,6 +51,10 @@
 
     void setBackgroundDataSetting(boolean allowBackgroundData);
 
+    boolean getMobileDataEnabled();
+
+    void setMobileDataEnabled(boolean enabled);
+
     boolean tether(String iface);
 
     boolean untether(String iface);