CEF3: OnApplicationExit throws AccessViolationException with WinForms

[perlun]

Slightly related to #210. If you shut down the app "too quickly", an exception gets thrown. I suspect this could be similar to the issue detected in 7b74e21. Has to be investigated.

[perlun]

I think it may have to do with not all requests finishing loading (or not all events having fired afterwards), or something like that. Must be fixed before CEF3 WinForms can be considered "stable".

[dmariani]

This error only seems to happen on x64. It doesn't happen on x86.

[perlun]

@dmariani, are you sure? I wonder if it isn't more a matter of "Debug" vs "Release" configurations?

[jornh]

Well, I think you are both right 😄 I experience this with current master branch only in the x64 | Debug combination,

With Win32 it seems to be reduced to:
A first chance exception of type 'System.NullReferenceException' occurred in CefSharp.Core.dll

[amaitland]

@jornh Is this issue still outstanding? If so do you have a list of steps to reproduce?

[perlun]

This one I am extremely pleased that you guys managed to resolve! Great work, @JanEggers! (and also you others who participated in the discussion)