According to Chris Cox, one of the Adobe Photoshop developers, when asked about making Shadows and Highlights an adjustment layer the problem is that the effect looks beyond the immediate pixel at the neighbours, so most normal adjustment layers and tonal filters won't do the same thing. That said, ejn is right - the closest you could get would be to use a curves filter/adjustment, perhaps filtered by loading the image's luminosity as a mask (ctrl(Win)/cmd(Mac)-click the RGB channel to make as election based on brightness).