To enable custom handling of antiforgery validation failures, use an
`AntiforgeryValidationFailedResult` which is just a `BadRequestResult`
but allows to be identified explicitly inside always-running result
filters using the `IAntiforgeryValidationFailedResult` marker interface.
- #3612 subpart 2 of 2
- merge `ActionConstraintsWebSite`, `AntiforgeryTokenWebSite` and `ContentNegotiationWebSite` into `BasicWebSite`
- remove tests depending on `ErrorReporterMiddleware` in merged sites; not used in `BasicWebSite`
- delete `CompositeViewEngineWebSite`, `Microsoft.AspNet.Mvc.ViewEngines.CompositeViewEngineTest` covers cases
- delete `CorsMiddlewareWebsite`, soon to be in Cors repo (see aspnet/CORS#57)
- remove `SendFileMiddleware` from FilesWebSite, unused there
Patrick Westerhoff
Kiran Challa
N. Taylor Mullen
Doug Bunting