Bug 1420312 - Followup to only mark frame as modified during retained building, since otherwise it won't be restored.

--HG--
extra : rebase_source : 675d7b40da6c41f2b2bc1513bee72e3361cbcd33

layout/generic/nsFrame.cpp

@@ -2758,8 +2758,10 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
 
     // We rebuild everything within preserve-3d and don't try
     // to retain, so override the dirty rect now.
-    dirtyRect = visibleRect;
-    aBuilder->MarkFrameModifiedDuringBuilding(this);
+    if (aBuilder->IsRetainingDisplayList()) {
+      dirtyRect = visibleRect;
+      aBuilder->MarkFrameModifiedDuringBuilding(this);
+    }
   }
 
   bool inTransform = aBuilder->IsInTransform();