Improve Accessibility Reliability

[carlos-zamora]

Summary of the Pull Request

Remove WindowUiaProvider entry points
Make TerminalAutomationPeer not crash the app if creation failed.

References

PR Checklist

• Closes nothing
• CLA signed.
• Tests added/passed
• Requires documentation to be updated
• I'm a core contributor

Detailed Description of the Pull Request / Additional comments

WindowUiaProvider was something I thought we needed. We still need it for signaling (maybe). But it sometimes can crash because it's not hooked up properly at all. For now, I removed all entry points. After the signaling model gets added for #2447, I'll decide if we actually need to remove it.

Also surrounded the TerminalControlAutomationPeer with a try/catch. If we don't have everything we need to create the AutomationPeer yet, we'll just catch it and move forward.

Validation Steps Performed

[DHowett-MSFT]

Do we know whether the TCAP gets created eventually even if we return nullptr a couple times?

[zadjii-msft]

Maybe we should add a note that if we do fail to make the TCAP initially, TermControl::OnCreateAutomationPeer will be called again later, so we'll have another chance.

[miniksa]

Approved hoping you commit the already requested changes by others before merging.

[DHowett-MSFT]

Just need confirmation on the question, then we're good to go.

[carlos-zamora]

Do we know whether the TCAP gets created eventually even if we return nullptr a couple times?

Using trace, I know that we still create the TCAP. So, this should be fine.

[ghost]

🎉Windows Terminal Preview v0.5.2661.0 has been released which incorporates this pull request.:tada:

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