BackgroundTaskRunner - add Hosted option, refactor some tasks

Conflicts:
	src/Umbraco.Web/Scheduling/BackgroundTaskRunner.cs

src/Umbraco.Tests/Scheduling/BackgroundTaskRunnerTests.cs

@@ -884,14 +884,6 @@ namespace Umbraco.Tests.Scheduling
             }
 
             public override bool RunsOnShutdown { get { return false; } }
-
-            protected override void Dispose(bool disposing)
-            {
-                Disposed = true;
-                base.Dispose(disposing);
-            }
-
-            public bool Disposed { get; private set; }
         }
 
         private class MyTask : BaseTask

src/Umbraco.Web/Scheduling/BackgroundTaskRunner.cs

@@ -90,7 +90,8 @@ namespace Umbraco.Web.Scheduling
             _options = options;
             _logPrefix = "[" + name + "] ";
             
-            HostingEnvironment.RegisterObject(this);
+            if (options.Hosted)
+                HostingEnvironment.RegisterObject(this);
 
             if (options.AutoStart)
                 StartUp();

src/Umbraco.Web/Scheduling/BackgroundTaskRunnerOptions.cs

@@ -15,6 +15,8 @@ namespace Umbraco.Web.Scheduling
             LongRunning = false;
             KeepAlive = false;
             AutoStart = false;
+            PreserveRunningTask = false;
+            Hosted = true;
         }
 
         /// <summary>
@@ -36,9 +38,16 @@ namespace Umbraco.Web.Scheduling
         public bool AutoStart { get; set; }
 
         /// <summary>
-        /// Gets or setes a value indicating whether the running task should be preserved
+        /// Gets or sets a value indicating whether the running task should be preserved
         /// once completed, or reset to null. For unit tests.
         /// </summary>
         public bool PreserveRunningTask { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the runner should register with (and be
+        /// stopped by) the hosting. Otherwise, something else should take care of stopping
+        /// the runner. True by default.
+        /// </summary>
+        public bool Hosted { get; set; }
     }
 }

src/Umbraco.Web/Scheduling/LatchedBackgroundTaskBase.cs

@@ -63,15 +63,22 @@ namespace Umbraco.Web.Scheduling
 
         protected virtual void Dispose(bool disposing)
         {
-            // lock on _latch instead of creating a new object as _timer is
+            if (disposing == false) return;
+
+            // lock on _latch instead of creating a new object as _latch is
             // private, non-null, readonly - so safe here
             lock (_latch)
             {
                 if (_disposed) return;
                 _disposed = true;
-
-                _latch.Dispose();                
+                _latch.Dispose();
+                DisposeResources();
             }
         }
+
+        protected virtual void DisposeResources()
+        { }
+
+        public bool Disposed { get {  return _disposed; } }
     }
 }

src/Umbraco.Web/Scheduling/RecurringTaskBase.cs

@@ -84,19 +84,13 @@ namespace Umbraco.Web.Scheduling
         /// and returning a value indicating whether to repeat the task.</returns>
         public abstract Task<bool> PerformRunAsync(CancellationToken token);
 
-        protected override void Dispose(bool disposing)
+        protected override void DisposeResources()
         {
-            // lock on _timer instead of creating a new object as _timer is
-            // private, non-null, readonly - so safe here
-            lock (_timer)
-            {
-                if (_disposed) return;
-                _disposed = true;
+            base.DisposeResources();
 
-                // stop the timer
-                _timer.Change(Timeout.Infinite, Timeout.Infinite);
-                _timer.Dispose();
-            }
+            // stop the timer
+            _timer.Change(Timeout.Infinite, Timeout.Infinite);
+            _timer.Dispose();
         }
     }
 }