Ignore No Data Changed Notifications

We're adding a "No Data Changed" notification to the framework for
K/V backups where no data has changed. LocalTransport has no use
for this notification so we'll ignore it if we see it.

Test: m -j RunBackupFrameworksServicesRoboTests
Bug: 147481066
Change-Id: Ida934f2a17367c430f3411ce1a457515c59746fd

packages/LocalTransport/src/com/android/localtransport/LocalTransport.java

@@ -211,6 +211,12 @@ public class LocalTransport extends BackupTransport {
 
     private int performBackupInternal(
             PackageInfo packageInfo, ParcelFileDescriptor data, int flags) {
+        if ((flags & BackupTransport.FLAG_DATA_NOT_CHANGED) != 0) {
+            // For unchanged data notifications we do nothing and tell the
+            // caller everything was OK
+            return BackupTransport.TRANSPORT_OK;
+        }
+
         boolean isIncremental = (flags & FLAG_INCREMENTAL) != 0;
         boolean isNonIncremental = (flags & FLAG_NON_INCREMENTAL) != 0;