Both the biscuit and the chocolate have to be blessed and one need pronounce only the blessing over the main components, thus for a chocolate croissant one would say the blessing over the dough, and skip the blessing over the chocolate.
Both the biscuit and the chocolate have to be blessed, and one needs to pronounce only the blessing over the primary ingredients. Therefore, for a chocolate croissant, you would bless the dough and skip the blessing over the chocolate.