Reduce heat to medium; add remaining 1 tablespoon oil and 1 tablespoon butter. Add mushrooms; cook 2 minutes, stirring occasionally, until lightly browned. Add onion, carrot and celery; cook about 6 minutes or until vegetables are softened. Add garlic; cook and stir 1 minute. Add white wine; cook 7 to 10 minutes, stirring occasionally, until reduced by half. Stir in tomatoes, broth and rosemary. Heat to boiling. Reduce heat to low. Add chicken breasts; simmer 20 to 25 minutes or until juice of chicken is clear when center of thickest part is cut (at least 165°F).