Add external dependency API.

An APN will not be connected to if some external dependency is not met.

bug:3486704
Change-Id: I7d94df343b260013efd11faa978deb13f07f1389
diff --git a/core/java/android/bluetooth/BluetoothTetheringDataTracker.java b/core/java/android/bluetooth/BluetoothTetheringDataTracker.java
index c08f14f..a7b0037 100644
--- a/core/java/android/bluetooth/BluetoothTetheringDataTracker.java
+++ b/core/java/android/bluetooth/BluetoothTetheringDataTracker.java
@@ -300,4 +300,8 @@
         msg = mCsHandler.obtainMessage(EVENT_STATE_CHANGED, mNetworkInfo);
         msg.sendToTarget();
     }
+
+    public void setDependencyMet(boolean met) {
+        // not supported on this network
+    }
 }