Implement IListSource on LocalView and EntityQueryable to further direct data binding

[ajcvickers]

Issues #8898 #8899

[divega]

Looks good. Did you have a chance to check if WPF databinding also calls IListSource.GetList()?

[ajcvickers]

No, would it change the decision to do this depending on the answer?

[divega]

No, would it change the decision to do this depending on the answer?

No, I think this PR is fine regardless.

What I am still concerned about is the decision to deviate from what we had in EF6. I.e. .Local used to returned an ordered collection that could be used directly for WPF-like databinding but now you need another call to ToObservableCollection() which won't be discoverable unless in binding to these objects directly causes the exception.

[divega]

That is why #8898 says

... but we also need to verify that doing so will help for WPF.

[ajcvickers]

I'll leave #8898 open after merging this and we can bring it back to triage to discuss the priority of doing this investigation.