cefclient: alloy: Popup window non-responsive when using --use-default-popup

[stephanema1]

Describe the bug
This bug is already described in cefsharp/CefSharp#4488 .

To Reproduce
Steps to reproduce the behavior:

1. download https://cef-builds.spotifycdn.com/cef_binary_113.1.1%2Bgfef20aa%2Bchromium-113.0.5672.63_windows64_beta_client.tar.bz2
2. run cefclient.exe --multi-threaded-message-loop --no-sandbox --enable-gpu --use-default-popup
3. Open a Website/html file with a link to a pdf line <a href="test.pdf" target="_blank">test.pdf</a>
4. cklick on the test.pdf link, the pdf is shown in a second window.
5. close the first windows (mein window)
6. the second window with the pdf now schows only black content and the process never closes
   (you kann only kill it with the task manager)

Expected behavior
When I execute the step 5. from above I expect that all windows are closed and that the process terminates.

Screenshots

Versions (please complete the following information):

• OS: Windows 10 (21H2)
• CEF Version: 110.0 or the actual beta (I suppose all are affected)

Additional context
Does the problem reproduce with the cefclient or cefsimple sample application at the same version?
Yes

Does the problem reproduce with Google Chrome at the same version?
No

Add any other context about the problem here.

[magreenblatt]

A similar issue reproduces with:

1. Run cefclient.exe --use-default-popup
2. Select Tests > New Popup
3. Close the main window
4. Notice that the remaining popup window is unresponsive

[magreenblatt]

cefclient.exe --use-default-popup works fine for me in M116 and newer (both Alloy and Chrome).

[magreenblatt]

OOPS, missed the bit about "Close the main window"

[magreenblatt]

Works fine with Chrome, still an issue for Alloy.

[magreenblatt]

This is currently crashing at M128 in RootWindowViews::GetDelegateForPopup due to an invalid cast. |client| is a DefaultClientHandler instead of a ClientHandlerStd

[magreenblatt]

This still reproduces at M128 (tested on Windows 11):

1. Run cefclient.exe --use-alloy-style --use-native --use-default-popup
2. Select Tests > New Popup
3. Close the main window
4. Notice that the remaining popup window is unresponsive

Using --use-alloy-style --use-views --use-default-popup the popup window contents are black after step 2.

None of this reproduces after removing --use-alloy-style.