am b505ae41: Merge change 5459 into donut

Merge commit 'b505ae4195d9b8a93c71b1f9da6d7d8c3aaa3c08'

* commit 'b505ae4195d9b8a93c71b1f9da6d7d8c3aaa3c08':
  Make the BackupHelperDispatcher properly handle multiple helpers.