Move layout change resolution calls up to VisualElementRenderer

[hartez]

Description of Change

The change to on-demand layout resolution in 5.0.0-pre2 moved the layout resolution to the layout renderers. Unfortunately, this meant that some ContentView uses (13492) and any custom renderer which replaced the layout renderers (13418) would not update their layout changes properly.

These changes move the layout resolution call to the base VisualElementRenderer class on each platform; this way, they encompass content views and any custom layout renderers.

Issues Resolved

• fixes [Bug] Issue changing visibility of any control when using ViewRenderer on 5.0 #13418
• fixes [Bug] [UWP] LayoutChildren method is not called in custom control after upgrade Xamarin.Forms 5.0 #13492
• fixes [Bug] [iOS] CollectionView does not display items if IsVisible modified via a binding/trigger #13551
• fixes [Bug] Regression: 5.0.0-pre5 often fails to draw dynamically loaded collection view content #13126

API Changes

None

Platforms Affected

• iOS
• Android
• UWP

Behavioral/Visual Changes

None

Before/After Screenshots

Not applicable

Testing Procedure

Unfortunately, this one is hard to write a test for without breaking all of Control Gallery. Best we can do is load up the repro projects from #13418 and #13492, apply the NuGet package from this PR, and verify that the problems are fixed.

For #13551 there is an automated UI test.

PR Checklist

• Targets the correct branch
• Tests are passing (or failures are unrelated)

[PureWeen]

Same UITest across all iOS runs failed

https://dev.azure.com/xamarin/public/_releaseProgress?releaseId=2840&_a=release-environment-extension&environmentId=136487&extensionId=ms.vss-test-web.test-result-in-release-environment-editor-tab

[hartez]

Same UITest across all iOS runs failed

https://dev.azure.com/xamarin/public/_releaseProgress?releaseId=2840&_a=release-environment-extension&environmentId=136487&extensionId=ms.vss-test-web.test-result-in-release-environment-editor-tab

Yeah, looks like this is somehow busting the default (text-only) cells. Looking into it.

[hartez]

Okay, all relevant tests are passing. iOS 12 lane just isn't running, the iOS 14 failures are the known ListView issues, and the Android stuff is just flaky tests.

[rmarinho]

Tested the nuget on the repos, and works as expected. I can see the controls now.