Merge "Destroy saved surfaces if one of the last visible windows gets removed" into nyc-dev
am: 15818e1156

* commit '15818e1156101f1d3a01009e7bc223d8ae88546d':
  Destroy saved surfaces if one of the last visible windows gets removed

Change-Id: I96e3ac246e18f1b6cc222ef847275ce15043b441