ADAL.NET 5.x needs to provide an extensibility mechanism so that partners provide their own Web View

[jmprieur]

Is your feature request related to a problem? Please describe.
Some partners need to provide their own Web View

Describe the solution you'd like
Like in MSAL.NET, provide an extensibility mechanism: a new interface ICustomWebUi to be implemented by extenders

namespace Microsoft.IdentityModel.Clients.ActiveDirectory.Extensibility {
    public interface ICustomWebUi {
        Task<Uri> AcquireAuthorizationCodeAsync(Uri authorizationUri, Uri redirectUri);
    }

On the .NET Framework - both .NET Fx and .NET Core - provide a new constructor to PlatformParameters

  public class PlatformParameters : IPlatformParameters {
        public PlatformParameters(PromptBehavior promptBehavior, ICustomWebUi customWebUi);
        public ICustomWebUi CustomWebUi { get; }
    }

Add more error messages to surface errors with extensions:

    public static class AdalError {
        public const string CustomWebUiRedirectUriMismatch = "custom_webui_invalid_mismatch";
        public const string CustomWebUiReturnedInvalidUri = "custom_webui_returned_invalid_uri";
        public const string HttpRequestTimeoutResilience = "http_request_timeout";
        public const string NetStandardCustomWebUi = "netcore_custom_webui";
        public const string StateMismatchError = "state_mismatch";
    }

and in .NET core provide both the class and the constructor
See https://aka.ms/msal-net-3x for details about the MSAL.NET

[trwalke]

Addressed in ADAL V5.0.0-preview