1. Add oil to crock pot. Sprinkle chicken with salt and pepper. Add chicken, garlic and mushrooms to crock pot and pour in wine. Cover; and cook on low heat for 5 to 6 hours.
2. Remove chicken from crock pot; place on plate and tent with foil to keep warm.
3. In small, blend water and cornstarch until smooth. Raise heat to high on crock pot and stir in cornstarch mixture; cover and cook for 10 minutes or until sauce is slightly thickened.
4. Return chicken to crock pot; and cook on high temperature for 5 minutes until chicken is hot.
5. Spoon mushroom mixture over chicken breasts and garnish with parsley to serve.