Spray 5- to 6-quart slow cooker with cooking spray. In large resealable food-storage plastic bag, place beef, flour and 1/2 teaspoon each of the salt and pepper. Seal bag; shake to coat beef.
In 5-quart Dutch oven, heat oil over medium-high heat. Cook beef in oil until brown on all sides. Place in slow cooker. Scatter prechopped vegetables and carrots around beef. Add tomatoes, broth, water, barley, Italian seasoning and remaining 1/2 teaspoon each salt and pepper.
Cover; cook on Low heat setting 8 hours or until beef is tender. Remove beef from slow cooker to plate; shred beef, using 2 forks. Return beef to slow cooker.