LayerTreeHost construction race condition fix#1517

tomasz-karczewski-red wants to merge 1 commit intoWebPlatformForEmbedded:wpe-2.38WebPlatformForEmbedded/WPEWebKit:wpe-2.38from

LibertyGlobal:tkarczewski/2.38/LayerTreeHost_construction_raceLibertyGlobal/WPEWebKit:tkarczewski/2.38/LayerTreeHost_construction_raceCopy head branch name to clipboard