Can Chipotle’s boss turn Starbucks around?

Chief executives like to measure their worth in hard currency. One yardstick is their pay. Another is the market’s reaction when they move jobs. Howard Schultz has twice returned to the helm of Starbucks, the coffee giant he built up from a handful of trendy shops in Seattle. Shareholders greeted him cautiously both times. But they have given a rapturous welcome to Brian Niccol, the current boss of Chipotle Mexican Grill, a chain of…