Preheat oven to 300 degrees. Whisk wine, broth, cranberry concentrate and flour to blend in medium bowl; pour into 15x10x2-inch roasting pan. Mix in onion, garlic and rosemary. Sprinkle brisket on all sides with salt and pepper. Place brisket, fat side up, in roasting pan. Spoon some of wine mixture over. Cover pan tightly with heavy-duty foil.
Bake brisket until very tender, basting with pan juices every hour, about 3-1/2 hours. Transfer brisket to plate; cool 1 hour at room temperature. Thinly slice brisket across grain. Arrange slices in pan with sauce, overlapping slices slightly. (Brisket can be prepared 2 days ahead. Cover and refrigerate.).
Preheat oven to 350 degrees. Place mushrooms and cranberries in sauce around brisket. Cover pan with foil. Bake until mushrooms are tender and brisket is heated through, about 30 minutes (40 minutes if brisket has been refrigerated.).
Transfer sliced brisket and sauce to platter and serve.