fix: replace browseable_message's implementation with wx.html2.WebView

[pauliyobo]

Link to issue number:

fixes #363

Summary of the issue:

Documents which have HTML tables without any caption or header may not be represented properly to a screen reader. This seems to be caused by the backend implementation we currently use to display any HTML dialog

Description of how this pull request fixes the issue:

This PR aims to replace the previous implementation with wx.html2.WebView

Testing performed:

Manual

Known issues with pull request:

None

cc @cary-rowen

[cary-rowen]

I tested this and found two things:

1. The webView does not get focus. Clicking with the mouse will give it focus.
2. Unfortunately, Improve EPUB table accessibility: semantic header detection and structure enforcement #363 can still be reproduced even when the webView has focus.

[pauliyobo]

Interesting for sure.
I wonder if it's selecting an older backend for you, as the table is rendered correctly here.

As for the focus problem, it seems to work on my end by using wx.UiActionSimulator, I wonder if additional steps steps are needed to make it work consistently.
Hm, I'll see if I can come up with other approaches, but if #362 is a blocker it could also be merged, if nothing else temporarily until a better solution is found.

[cary-rowen]

Hello @pauliyobo
It seems that the key issue I mentioned earlier has been fixed by nvaccess/nvda#17273.
However, #363 can still be reproduced.

[cary-rowen]

Hello @pauliyobo
Can we consider temporarily merging #362 and then tracking this as a separate to-do item?

[pauliyobo]

Hello, sorry for the long wait.
Indeed, I agree we can proceed with this approach.