Network data activity change intent for network interfaces.

The activity notification is received from netd, an intent
DATA_ACTIVITY_CHANGE is then raised for other part of the system to
consume.

Change-Id: Idfcc4763c51c5b314c57f546c12557082f06bebf
diff --git a/services/java/com/android/server/CommonTimeManagementService.java b/services/java/com/android/server/CommonTimeManagementService.java
index 9a25d2e..c316733 100644
--- a/services/java/com/android/server/CommonTimeManagementService.java
+++ b/services/java/com/android/server/CommonTimeManagementService.java
@@ -120,6 +120,8 @@
             reevaluateServiceState();
         }
         public void limitReached(String limitName, String iface) { }
+
+        public void interfaceClassDataActivityChanged(String label, boolean active) {}
     };
 
     private BroadcastReceiver mConnectivityMangerObserver = new BroadcastReceiver() {