Removed code which cleared the backbuffer to white before rendering. bug 49779 sr=roc+moz r=rods@netscape.com

view/src/nsViewManager2.cpp

@@ -760,23 +760,6 @@ void nsViewManager2::Refresh(nsIView *aView, nsIRenderingContext *aContext, cons
 
 	localcx->SetClipRect(trect, nsClipCombine_kReplace, result);
 
-  if ((aUpdateFlags & NS_VMREFRESH_DOUBLE_BUFFER) && ds)
-  {
-    // XXX: This should not be needed. The frames should
-    // paint the background for the area cleared, but when the 
-    // document is empty there aren't any frames to clear the 
-    // background. In addition, frames sometimes
-    // do not paint the entire extent of the damaged rect.
-    // However, this should be fixed in the frame's not here.
-    
-    // Clear the background of the area about to be rendered to.
-    // If this is not done, garbage (stale bits) from the backbuffer
-    // are copied forward.
-    nscolor col = NS_RGB(255,255, 255);
-    localcx->SetColor(col);
-    localcx->FillRect(trect);
-  }
-
 	RenderViews(aView, *localcx, trect, result);
 
 	if ((aUpdateFlags & NS_VMREFRESH_DOUBLE_BUFFER) && ds)