Not a clean shutdown in examples, when closing app while browser is still loading a website

[cztomczak]

Steps to reproduce:

1. Type "test" in Google
2. Load speed test website
3. Close app while it's still loading
4. Error in logs occurs:

[CEF Python] ERROR: Shutdown called, but there are still browser references alive

It doesn't reproduce every time. Issue occurs in all examples.

I will try to fix this by always forcing shutdown of browsers and then run message loop work for at least 0.2 sec. Currently it runs for 0.1 sec. Issue also occurs in hello_world.py which uses MessageLoop(), but looks like calling some message loop work here is also required.

[cztomczak]

Fixed in bfc0a25. Related comments and new code here:

cefpython/src/cefpython.pyx

Line 861 in bfc0a25

# Run some message loop work, force closing browsers and then run

. v55.2 released, please test.