Internals part #1: platform backends

[maxkatz6]

What does the pull request do?

Hides (almost) all of interface implementations and public API types that should be internal in these assemblies:

• Avalonia.Android
• Avalonia.Browser
• Avalonia.iOS
• Avalonia.Native
• Avalonia.X11
• Avalonia.FreeDesktop (ended up with no public members at all, as it is directly used from the Avalonia.X11)
• Avalonia.Win32
• Avalonia.Skia
• Avalonia.Direct2D

Note, win32 automation COM interfaces weren't made internal, as whole automation stops working because of that. I couldn't figure it out quickly, so moved it out of this PR.

Also, it seems to not be possible to disabled resources generation from _UpdateAndroidResgen, so these 1800 lines of public API are still there.

It should be easier to review changes with this commit from API-listing generator branch: aeea42f

Part of #6666

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0029978-beta. (feed url: https://pkgs.dev.azure.com/AvaloniaUI/AvaloniaUI/_packaging/avalonia-all/nuget/v3/index.json) [PRBUILDID]

[grokys]

Note, win32 automation COM interfaces weren't made internal, as whole automation stops working because of that.

Yeah I ran into this: it seems that COM interfaces need to be public to work with the inbuilt COM interop? A pretty strange requirement, and one that I've not actually seen documented anywhere. @jkoritzinsky maybe you might have some insight here?

In the longer-term we need to move away from .NET's inbuilt COM support but that's not possible yet.

[jkoritzinsky]

It looks like the interfaces are marked [ComVisible(true)]. The ComVisible attribute depends on visibility. Since you're consuming these interfaces instead of authoring them (aka Windows defines them, not you), you should mark them with [ComImport] instead of [ComVisible(true)]. Then it should work.