Bug 1022612. Part 18: When ComputeVisibility returns false, RecomputeVisibility should avoid painting the item. r=mattwoodrow

--HG--
extra : rebase_source : b11f832b412b75e9868306908a5e08fe9724a603

layout/base/nsDisplayList.cpp

@@ -1737,8 +1737,10 @@ nsDisplayItem::RecomputeVisibility(nsDisplayListBuilder* aBuilder,
   // When we recompute visibility within layers we don't need to
   // expand the visible region for content behind plugins (the plugin
   // is not in the layer).
-  if (!ComputeVisibility(aBuilder, aVisibleRegion, nsRect()))
+  if (!ComputeVisibility(aBuilder, aVisibleRegion, nsRect())) {
+    mVisibleRect = nsRect();
     return false;
+  }
 
   nsRegion opaque = TreatAsOpaque(this, aBuilder);
   aBuilder->SubtractFromVisibleRegion(aVisibleRegion, opaque);