Bug 586683 - ImageContainers can have no manager. r=Bas a=bustage

gfx/layers/ImageLayers.h

@@ -220,7 +220,7 @@ public:
    */
   void SetContainer(ImageContainer* aContainer) 
   {
-    NS_ASSERTION(aContainer->Manager() == Manager(), 
+    NS_ASSERTION(!aContainer->Manager() || aContainer->Manager() == Manager(), 
                  "ImageContainer must have the same manager as the ImageLayer");
     mContainer = aContainer;  
   }