In a 4 to 5 quart slow cooker, combine mushrooms, undrained tomatoes, chicken broth, onion, wine, olives, curry powder, thyme, salt, and pepper. Add artichoke hearts. Place chicken on top, spoon some of the tomato mixture over the chicken.
Cover and cook on low heat setting for 7 to 8 hours or on high heat setting for 3 1/2 to 4 hours.
With a slotted spoon, transfer chicken and artichokes to a serving bowl. Cover with foil to keep warm.
If using low heat setting, turn to high heat setting. Combine in a small bowl cornstarch and water. Stir into mixture in cooker. Cover and cook for 15 minutes more or until thickened. Spoon tomato mixture over chicken and artichokes.