Called when the window is about to unload its resources.
At this point, the document is still visible and the BeforeUnloadEvent
event will be canceled if the return value of this method is false.
In Electron, handleCloseRequestEvent is is run instead.
Notify the browser that we do not want to unload.
Notes:
The beforeunload event
Implement the mechanism to detect unloading of the page.
Returns a list of actions that FrontendApplicationContributions would like to take before shutdown It is expected that this will succeed - i.e. return an empty array - at most once per session. If no vetoes are received during any cycle, no further checks will be made. In that case, shutdown should proceed unconditionally.