Remove [Obsolete] InterfaceConsts classes

[jpobst]

Today when we encounter constants in Java interfaces that we have changed to C# Enums we generate the following:

[Register ("android/view/inputmethod/InputConnection", ApiSince = 3, DoNotGenerateAcw=true)]
public abstract class InputConnection : Java.Lang.Object {

	internal InputConnection ()
	{
	}

	// Metadata.xml XPath field reference: path="/api/package[@name='android.view.inputmethod']/interface[@name='InputConnection']/field[@name='GET_EXTRACTED_TEXT_MONITOR']"
	[Register ("GET_EXTRACTED_TEXT_MONITOR")]
	[Obsolete ("This constant will be removed in the future version. Use Android.Views.InputMethods.TextExtractFlags enum directly instead of this field.")]
	public const Android.Views.InputMethods.TextExtractFlags GetExtractedTextMonitor = (Android.Views.InputMethods.TextExtractFlags) 1;

	// Metadata.xml XPath field reference: path="/api/package[@name='android.view.inputmethod']/interface[@name='InputConnection']/field[@name='GET_TEXT_WITH_STYLES']"
	[Register ("GET_TEXT_WITH_STYLES")]
	[Obsolete ("This constant will be removed in the future version. Use Android.Views.InputMethods.GetTextFlags enum directly instead of this field.")]
	public const Android.Views.InputMethods.GetTextFlags GetTextWithStyles = (Android.Views.InputMethods.GetTextFlags) 1;

	// Metadata.xml XPath field reference: path="/api/package[@name='android.view.inputmethod']/interface[@name='InputConnection']/field[@name='INPUT_CONTENT_GRANT_READ_URI_PERMISSION']"
	[Register ("INPUT_CONTENT_GRANT_READ_URI_PERMISSION", ApiSince = 25)]
	[Obsolete ("This constant will be removed in the future version. Use Android.Views.InputMethods.InputContentFlags enum directly instead of this field.")]
	public const Android.Views.InputMethods.InputContentFlags InputContentGrantReadUriPermission = (Android.Views.InputMethods.InputContentFlags) 1;
}

[Register ("android/view/inputmethod/InputConnection", ApiSince = 3, DoNotGenerateAcw=true)]
[global::System.Obsolete ("Use the 'InputConnection' type. This type will be removed in a future release.")]
public abstract class InputConnectionConsts : InputConnection {

	private InputConnectionConsts ()
	{
	}
}

These have been marked as [Obsolete] for at least 3 years. Can we take the opportunity at our next major revision bump to remove them?

[jonpryor]

Can we take the opportunity at our next major revision bump to remove them?

No. Our major version numbers are tied with the Android OS major version number, which means we'll probably be bumping "soon", likely as part of d16-3 (i.e. "now").

Can we ever take the opportunity to remove them? Maybe. There are unsubstantiated rumors that the iOS team may take some API breaks as part of the eventual .NET 5 migration, and we may want to do so as well. However, the entire .NET 5 plan is full of unknowns, which may force its own breakage (e.g. removal of AppDomain.CreateDomain()) or otherwise force our hand.

Source compatibility will almost certainly be need to be maintained to the greatest extent possible.

[jpobst]

These are removed from bindings beginning with API-R via #509. They will remain in previous versions of bindings as [Obsolete (iserror: true)].