[Fix] Add missing C# events in the UIAdaptivePresentationControllerDelegate and UIPopoverPresentationControllerDelegate classes.

[mandel-macaque]

In order to understand this PR you need to know the following details:

• UIAdaptivePresentationControllerDelegate: This class contains GetAdaptivePresentationStyle as an overloaded method. This means that the generator cannot generate the C# events for both implementations of the method.
• GetAdaptivePresentationStyle (UIPresentationController controller) as per apple documentation should not be used if the method that takes the trait collection can be used: In iOS 8.3 and later, use the adaptivePresentationStyleForPresentationController:traitCollection:
• The C# event added is using the recommended method by apple will only be present in the 8.3 version. Older versions won't have the event and will have to implement the GetAdaptivePresentationStyle (UIPresentationController controller) on in a subclass.
• The extension method that used to be generated won't be present since the generator will ignore it.

Taking into account the above, I moved the old method implementation to a diff file so that it is not picked up by the generator, that way the generator can create all the C# events without change and will ignore the old method. The old API is maintained + we add the new events only for version of ios 8.3 +

[dnfclas]

Hi @mandel-macaque, I'm your friendly neighborhood .NET Foundation Pull Request Bot (You can call me DNFBOT). Thanks for your contribution!
You've already signed the contribution license agreement. Thanks!

The agreement was validated by .NET Foundation and real humans are currently evaluating your PR.

TTYL, DNFBOT;

[chamons]

Looks reasonable to me (2nd set of eyes recommended though).

[dalexsoto]

Vey minor but param name could be just presentationController

[spouliot]

that's the existing signature so it should stay the same

[spouliot]

While it's fine I'm not sure it's a good idea to move generated code to manual bindings, e.g. it's extra maintenance (need to reflect generator changes in that code), the linker can't optimize it (by default) and adding [GeneratedCode] attribute is hackish and could bite us in the future.

What about adding a to be defined attribute to GetAdaptivePresentationStyle bindings and have the generator ignore it when Events= is used ?

That also needs a test case so we can ensure it works properly of < iOS 8.3.

[mandel-macaque]

@spouliot I did consider modifying the generator. In that case I would not use Events= since it might be misleading for other when reading the code. What about adding a new attribute to mark that it should be ignored in the generation of the events? Maybe something like [EventIgnored]. If adding a new attribute is a no no, we can always do DelegateName (null) and state that null will imply that the method will be ignored.

[rolfbjarne]

I agree with Sebastien about adding a new attribute/logic to the generator instead of moving code to manual bindings.

[mandel-macaque]

I just noticed I said the exact same thing :-/ I'll do the changes in the generator and we can agree on the attribute name later :)

[spouliot]

Closing as per comments (this will be a generator change).