[banshee] GStreamerSharp: protect call to event delegates

[Andrés Aragoneses <aaragoneses src gnome org>]

commit e26ae39dfb6ee1559ccc0e40606e9449e909bce3
Author: Andrés G. Aragoneses <knocte gmail com>
Date:   Wed Oct 30 13:15:49 2013 +0100

    GStreamerSharp: protect call to event delegates
    
    This is a good practice to avoid potential race conditions, that
    is already used in other events, and is best explained in:
    
    http://www.mono-project.com/Gendarme.Rules.Concurrency#ProtectCallToEventDelegatesRule
    
    or
    
    
https://github.com/spouliot/gendarme/wiki/Gendarme.Rules.Concurrency.ProtectCallToEventDelegatesRule%282.10%29

 .../Banshee.GStreamerSharp/VideoManager.cs         |   17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)
---
diff --git a/src/Backends/Banshee.GStreamerSharp/Banshee.GStreamerSharp/VideoManager.cs 
b/src/Backends/Banshee.GStreamerSharp/Banshee.GStreamerSharp/VideoManager.cs
index 64cfb30..bfbdb45 100644
--- a/src/Backends/Banshee.GStreamerSharp/Banshee.GStreamerSharp/VideoManager.cs
+++ b/src/Backends/Banshee.GStreamerSharp/Banshee.GStreamerSharp/VideoManager.cs
@@ -83,10 +83,17 @@ namespace Banshee.GStreamerSharp
             playbin.Bus.SyncMessage += OnSyncMessage;
             //if (videosink is Bin) { ((Bin)videosink).ElementAdded += OnVideoSinkElementAdded; }
 
-            if (PrepareWindow != null) {
-                PrepareWindow ();
+            RaisePrepareWindow ();
+        }
+
+        private void RaisePrepareWindow ()
+        {
+            var handler = PrepareWindow;
+            if (handler != null) {
+                handler ();
             }
         }
+
         public delegate void PrepareWindowHandler ();
         public event PrepareWindowHandler PrepareWindow;
 
@@ -225,8 +232,10 @@ namespace Banshee.GStreamerSharp
 
         private void RaiseVideoGeometry (int width, int height, int fps_n, int fps_d, int par_n, int par_d)
         {
-            if (VideoGeometry != null)
-                VideoGeometry (width, height, fps_n, fps_d, par_n, par_d);
+            var handler = VideoGeometry;
+            if (handler != null) {
+                handler (width, height, fps_n, fps_d, par_n, par_d);
+            }
         }
 
         public void WindowExpose (IntPtr window, bool direct)