Heat oil in large saute pan over medium-high heat. Season chicken with salt and pepper and sear in a large saute pan only to brown the skin not to cook through. Remove chicken and add the onions. Cook until tender, about 5 minutes, then add garlic and cook until fragrant. Add the chili sauce, raisins and sugar. Return the chicken to the skillet, skin side up and cover the pan tightly with aluminum foil then bake for 1 hour 15 minutes. Uncover pan, add sherry, water and fruit and bake for another 20 minutes.