Mix strawberries, sugar and cornstarch in large bowl. Set aside.
Roll dough out on lightly-floured surface. Use small bowl or glass (about 3½ inches in diameter) to cut out 20 rounds. Reroll scraps as necessary.
Place 10 dough circles on parchment-lined baking sheet. Fill center with strawberries and chocolate chips. Wet rim of dough with water. Top with second dough circle and press edges firmly to seal or use a fork to seal edges. Brush with egg whites.
Bake 15-20 minutes or until golden brown. Let cool before serving.