Add the cookie IsEssential flag and feature

src/Microsoft.AspNetCore.Http.Abstractions/CookieBuilder.cs

@@ -72,6 +72,12 @@ namespace Microsoft.AspNetCore.Http
         /// </summary>
         public virtual TimeSpan? MaxAge { get; set; }
 
+        /// <summary>
+        /// Indicates if this cookie is essential for the application to function correctly. If true then
+        /// consent policy checks may be bypassed. The default value is false.
+        /// </summary>
+        public virtual bool IsEssential { get; set; }
+
         /// <summary>
         /// Creates the cookie options from the given <paramref name="context"/>.
         /// </summary>
@@ -99,6 +105,7 @@ namespace Microsoft.AspNetCore.Http
                 HttpOnly = HttpOnly,
                 MaxAge = MaxAge,
                 Domain = Domain,
+                IsEssential = IsEssential,
                 Secure = SecurePolicy == CookieSecurePolicy.Always || (SecurePolicy == CookieSecurePolicy.SameAsRequest && context.Request.IsHttps),
                 Expires = Expiration.HasValue ? expiresFrom.Add(Expiration.Value) : default(DateTimeOffset?)
             };

src/Microsoft.AspNetCore.Http.Features/CookieOptions.cs

@@ -59,5 +59,11 @@ namespace Microsoft.AspNetCore.Http
         /// </summary>
         /// <returns>The max-age date and time for the cookie.</returns>
         public TimeSpan? MaxAge { get; set; }
+
+        /// <summary>
+        /// Indicates if this cookie is essential for the application to function correctly. If true then
+        /// consent policy checks may be bypassed. The default value is false.
+        /// </summary>
+        public bool IsEssential { get; set; }
     }
 }

src/Microsoft.AspNetCore.Http.Features/ITrackingConsentFeature.cs

@@ -0,0 +1,39 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNetCore.Http.Features
+{
+    /// <summary>
+    /// Used to query, grant, and withdraw user consent regarding the storage of user
+    /// information related to site activity and functionality.
+    /// </summary>
+    public interface ITrackingConsentFeature
+    {
+        /// <summary>
+        /// Indicates if consent is required for the given request.
+        /// </summary>
+        bool IsConsentNeeded { get; }
+
+        /// <summary>
+        /// Indicates if consent was given.
+        /// </summary>
+        bool HasConsent { get; }
+
+        /// <summary>
+        /// Indicates either if consent has been given or if consent is not required.
+        /// </summary>
+        bool CanTrack { get; }
+
+        /// <summary>
+        /// Grants consent for this request. If the response has not yet started then
+        /// this will also grant consent for future requests.
+        /// </summary>
+        void GrantConsent();
+
+        /// <summary>
+        /// Withdraws consent for this request. If the response has not yet started then
+        /// this will also withdraw consent for future requests.
+        /// </summary>
+        void WithdrawConsent();
+    }
+}