Robert Cluck

After winning a World Series bet, San Francisco Mayor Gavin Newsom enjoyed a mouthful of Texas barbecue ... compliments of Arlington, TX Mayor Robert Cluck. As TMZ first reported, Newsom and Cluck both agreed to ship the winning mayor a bunch of local delicious treats. Since the Giants beat the…

The Commissioner's Trophy isn't the only thing on the line when the Texas Rangers play the San Francisco Giants in the 2010 World Series -- two hometown mayors have each stepped up to the plate to make a serious bet on the outcome. TMZ has learned ... San Francisco Mayor Gavin Newsom (right) and…