Fix for 96528 -- crash on File/Exit with full-page xpcom plugin, r=peterl, sr=attinasi, a=asa, for 0.9.2 a=marek

git-svn-id: svn://10.0.0.236/branches/MOZILLA_0_9_2_BRANCH@101846 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/modules/plugin/nglsrc/nsPluginViewer.cpp

@@ -276,9 +276,8 @@ PluginViewerImpl::~PluginViewerImpl()
 
   if(mOwner) {
     nsIPluginInstance * inst;
-    mOwner->GetInstance(inst);
 
-    if(inst) {
+    if(NS_SUCCEEDED(mOwner->GetInstance(inst)) && inst) {
       nsCOMPtr<nsIPluginHost> host = do_GetService(kCPluginManagerCID);
       if(host)
         host->StopPluginInstance(inst);