am 07eac016: Merge change 4682 into donut

Merge commit '07eac016446c63711bebe6e553e98c02d1fe55a5'

* commit '07eac016446c63711bebe6e553e98c02d1fe55a5':
  Store the app signatures as part of the backup set

core/java/android/backup/BackupDataOutput.java

@@ -36,6 +36,7 @@ public class BackupDataOutput {
         }
     }
 
+    // A dataSize of -1 indicates that the record under this key should be deleted
     public int writeEntityHeader(String key, int dataSize) throws IOException {
         int result = writeEntityHeader_native(mBackupWriter, key, dataSize);
         if (result >= 0) {