Release Notes for v39.8.4

Fixes

Fixed an issue where nodeIntegrationInWorker overrides in setWindowOpenHandler were not honored for child windows sharing a renderer process with their opener. #50468 ^{(Also in 38, 40, 41)}
Fixed crash when handling JavaScript dialogs from windows opened with invalid or empty URLs. #50400 ^{(Also in 40, 41, 42)}
Fixed improper focus tracking in BaseWindow on MacOS. #50338 ^{(Also in 40, 41, 42)}
Fixed window freeze when failing to enter/exit fullscreen on macOS. #50341 ^{(Also in 40, 41, 42)}

Added support for using a proxy during yarn install. #50349 ^{(Also in 40, 41, 42)}
Backported fix for 485935305. #50440
Backported fix for 489381399. #50443
Backported fix for chromium:475877320. #50436
Backported fixes for 484751092, 487117772. #50461