Bug 701656 - Include the preserve-3d parent content in preserve-3d sorting. r=roc

layout/base/nsDisplayList.cpp

@@ -2610,7 +2610,7 @@ already_AddRefed<Layer> nsDisplayTransform::BuildLayer(nsDisplayListBuilder *aBu
 
   // Add the preserve-3d flag for this layer, BuildContainerLayerFor clears all flags,
   // so we never need to explicitely unset this flag.
-  if (mFrame->Preserves3D()) {
+  if (mFrame->Preserves3D() || mFrame->Preserves3DChildren()) {
     container->SetContentFlags(container->GetContentFlags() | Layer::CONTENT_PRESERVE_3D);
   }
   return container.forget();