Improving output cache filter.

- This change allows any shapes to be added to the Messages zone without causing the output cache to not kick in anymore.
- Using INotifier instead of INotificationManager to prevent invocation of INotificationProvider implementations.

src/Orchard.Web/Modules/Orchard.OutputCache/Filters/OutputCacheFilter.cs

@@ -19,6 +19,7 @@ using Orchard.Mvc.Filters;
 using Orchard.Services;
 using Orchard.Themes;
 using Orchard.UI.Admin;
+using Orchard.UI.Notify;
 using Orchard.Utility.Extensions;
 using System.Collections.Specialized;
 using Orchard.OutputCache.ViewModels;
@@ -39,6 +40,7 @@ namespace Orchard.OutputCache.Filters {
         private readonly ISignals _signals;
         private readonly ShellSettings _shellSettings;
         private readonly ICacheControlStrategy _cacheControlStrategy;
+        private readonly INotifier _notifier;
 
         TextWriter _originalWriter;
         StringWriter _cachingWriter;
@@ -57,8 +59,9 @@ namespace Orchard.OutputCache.Filters {
             ICacheService cacheService,
             ISignals signals,
             ShellSettings shellSettings,
-            ICacheControlStrategy cacheControlStrategy
-            ) {
+            ICacheControlStrategy cacheControlStrategy, 
+            INotifier notifier) {
+
             _cacheManager = cacheManager;
             _cacheStorageProvider = cacheStorageProvider;
             _tagCache = tagCache;
@@ -70,6 +73,7 @@ namespace Orchard.OutputCache.Filters {
             _signals = signals;
             _shellSettings = shellSettings;
             _cacheControlStrategy = cacheControlStrategy;
+            _notifier = notifier;
 
             Logger = NullLogger.Instance;
         }
@@ -343,9 +347,7 @@ namespace Orchard.OutputCache.Filters {
             }
 
             // don't cache the result if there were some notifications
-            // notifications can come from Notifier and NotificationProvider
-            var messagesZone = _workContextAccessor.GetContext(filterContext).Layout.Zones["Messages"] as Shape;
-            if (messagesZone != null && messagesZone.Items.Any()) {
+            if (_notifier.List().Any()) {
                 return;
             }