am 61080e26: am 461af5c8: am 7ab900ed: Merge change Ic8093c11 into eclair

Merge commit '61080e26799a2236ee87ef5cb35d0f461a5c835f'

* commit '61080e26799a2236ee87ef5cb35d0f461a5c835f':
  Hold a lock while we access the preview heap.