yaakovschectman c2cc8508b6 Reintroduce Windows lifecycle with guard for posthumous OnWindowStateEvent (flutter/engine#44344)
Previously, destruction of `Window` called `DestroyWindow`, which may
send `WM_KILLFOCUS` to the to-be-destroyed window. Because `Window`'s
destructor is called after `FlutterWindow`'s, the `FlutterWindow` vtable
was already destroyed at this point, and the subsequent call to the
virtual method `OnWindowStateEvent` would cause a crash. This PR
reintroduces the reverted changes for Windows lifecycle with a check
before calling the virtual method that the `FlutterWindow` object has
not yet been destructed.

https://github.com/flutter/flutter/issues/131872

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---------

Co-authored-by: Loïc Sharma <737941+loic-sharma@users.noreply.github.com>
2023-08-10 15:37:04 -04:00
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