Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Web/Cache/OutputCacheProvider.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Configuration.Provider;
+using System.Security.Permissions;
+using System.Web;
+
+namespace System.Web.Caching {
+    // the abstract base class implemented by all output cache providers
+    public abstract class OutputCacheProvider: ProviderBase {
+        // Returns the specified entry, or null if it does not exist.
+        public abstract Object Get(String key);
+        // Inserts the specified entry into the cache if it does not already exist, otherwise returns the existing entry.
+        public abstract Object Add(String key, Object entry, DateTime utcExpiry);
+        // Inserts the specified entry into the cache, overwriting an existing entry if present.
+        public abstract void Set(String key, Object entry, DateTime utcExpiry);
+        // Removes the specified entry from the cache.
+        public abstract void Remove(String key);
+    }
+}