build fix for gtk1 for 344323

widget/src/gtk/nsScreenManagerGtk.cpp

@@ -235,3 +235,8 @@ nsScreenManagerGtk :: GetNumberOfScreens(PRUint32 *aNumberOfScreens)
   
 } // GetNumberOfScreens
 
+NS_IMETHODIMP
+nsScreenManagerGtk :: ScreenForNativeWidget(void *nativeWidget, nsIScreen **aScreen)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}