[banshee] [ThickClient] Add AssertInMainThread calls to debug an NRE

[Gabriel Burt <gburt src gnome org>]

commit 1f8651ceb3744a1db46218eb3894206f26cbf15a
Author: Gabriel Burt <gabriel burt gmail com>
Date:   Tue Dec 14 19:12:06 2010 -0600

    [ThickClient] Add AssertInMainThread calls to debug an NRE

 .../Banshee.Sources.Gui/SourceModel.cs             |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs b/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs
index 8c729f9..f2ce25e 100644
--- a/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs
+++ b/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs
@@ -194,6 +194,7 @@ namespace Banshee.Sources.Gui
 
         public void AddSource (Source source, TreeIter parent)
         {
+            ThreadAssist.AssertInMainThread ();
             lock (sync) {
                 if (Filter != null && !Filter (source)) {
                     return;
@@ -234,6 +235,7 @@ namespace Banshee.Sources.Gui
 
         public void RemoveSource (Source source)
         {
+            ThreadAssist.AssertInMainThread ();
             lock (sync) {
                 TreeIter iter = FindSource (source);
                 if (!iter.Equals (TreeIter.Zero)) {
@@ -249,6 +251,7 @@ namespace Banshee.Sources.Gui
 
         public void Refresh ()
         {
+            ThreadAssist.AssertInMainThread ();
             Clear ();
             foreach (Source source in ServiceManager.SourceManager.Sources) {
                 AddSource (source);