The SetTitle function has been implemented in nsWindow, so it shouldn't be necessary to have stubs for this function here as well.

widget/src/xlib/nsWidget.cpp

@@ -333,11 +333,6 @@ void * nsWidget::GetNativeData(PRUint32 aDataType)
   }
 }
 
-NS_IMETHODIMP nsWidget::SetTitle(const nsString& aTitle)
-{
-  return NS_OK;
-}
-
 NS_IMETHODIMP nsWidget::SetTooltips(PRUint32 aNumberOfTips,
                                     nsRect* aTooltipAreas[])
 {

widget/src/xlib/nsWidget.h

@@ -87,7 +87,6 @@ public:
   virtual void*           GetNativeData(PRUint32 aDataType);
   NS_IMETHOD              SetColorMap(nsColorMap *aColorMap);
   NS_IMETHOD              Scroll(PRInt32 aDx, PRInt32 aDy, nsRect *aClipRect);
-  NS_IMETHOD              SetTitle(const nsString& aTitle); 
   NS_IMETHOD              SetMenuBar(nsIMenuBar * aMenuBar); 
   NS_IMETHOD              ShowMenuBar(PRBool aShow);
   NS_IMETHOD              IsMenuBarVisible(PRBool *aVisible);