Shapes on iOS fail to render if the bounds of the view is set prior to renderer creation

[PureWeen]

Description of Change

The ShapeRenderer was setup to UpdateSize only when the width/height changed. So in cases where the width/height were already set the native shape would never draw. This issue was present on shell because on shell when you switch Flyout Items all of the renderers get removed and will get re-added when navigating back. Because the xplat size of the Ellipse was already set then on the second navigation the native size would never get set. This issue probably manifests itself in other cases as well. For example, if someone sets the bounds of a shape before attaching a renderer it won't draw

Issues Resolved

• fixes [Bug] RadioButton and Shapes not re-rendering correctly in Shell and other cases of View Reuse #12245
• fixes [Bug] Path not loading in Xamarin ShellContent Tab once it is navigated back from other Tab #13225
• fixes [Bug] Shapes in SwipeView of a CollectionView/ListView has several issues #12911
• fixes Shapes.Path Not displayed on SwipeItemView #13096
• fixes [Bug] Shapes broken in Xamarin if used within NavigationPage once and navigated back #13164
• fixes [Bug] Shapes not loading in Xamarin ShellContent Tab once it is navigated back from other Tab #11924
• fixes [Bug] Android Shapes drawing Line disappears on page pop and returning back to the page won't draw again #11656
• fixes [Bug] Path not rendered on page reload #12844
• fixes [Bug][iOS] Shapes disappear in a Frame in a ListView when scrolled #12521
• fixes Path + Shell problem[Bug]  #13407

Platforms Affected

• iOS
• Android

Testing Procedure

• unit test attached
• You can test the nugets with the original sample as well if you'd like [Bug] RadioButton and Shapes not re-rendering correctly in Shell and other cases of View Reuse #12245

PR Checklist

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

[jsuarezruiz]

I just have a question, what is the reason for the DO-NOT-MERGE!!! label?

[PureWeen]

@jsuarezruiz DNM got added once I noticed your PR here #13167 that solves the same issue differently. So, wanted to make sure we got the best of both PRs merged together and then merged into 5.0.0

[jsuarezruiz]

We had several issues and PRs with a similar fix although with different examples, etc. I have reviewed all related PRs and issues and have grouped them into this PR.
Added the fix for Android too. In this way, this PR is an important fix that affects a large number of issues (marked as blocker).
Here are screenshots of the added examples:

[durandt]

Adding this just for reference in case other people stumble on this issue:

This PR also fixes a rendering crash on Android when a shape with a radial gradient would be added to a view outside of the current view hierarchy.

Error
Java.Lang.IllegalArgumentException: radius must be > 0

Fix
Upgrade to latest Xamarin.Forms 5.0.0 or apply the changes in ShapeRenderer from this changeset.