Bug 1022612. Part 12: Propagate NeedsTransparentSurface in ProcessDisplayItems. r=mattwoodrow

--HG--
extra : rebase_source : b7302f3457837f8308925ab67705e6279a80caf3

layout/base/FrameLayerBuilder.cpp

@@ -2742,6 +2742,11 @@ ContainerState::ProcessDisplayItems(nsDisplayList* aList,
       accumulateIntoThebesLayerData->Accumulate(this, item,
           opaquePixels, itemVisibleRect, itemDrawRect, itemClip);
     }
+
+    if (itemSameCoordinateSystemChildren &&
+        itemSameCoordinateSystemChildren->NeedsTransparentSurface()) {
+      aList->SetNeedsTransparentSurface();
+    }
   }
 
   aList->AppendToTop(&savedItems);