China’s top leader, Xi Jinping, met with Senator Chuck Schumer, the majority leader, in Beijing on Monday and expressed hopes of “peaceful coexistence” between China and the United States, even as escalating violence in the Middle East threatens to deepen a wedge between the two powers. “We have 1,000 reasons to make China-U.S. relations work well and not a single reason to make China-U.S. relations bad,” Mr. Xi said while meeting with the Democratic senator from New York. Mr. Xi’s amicable tone is likely to increase expectations that he will attend the Asia-Pacific Economic Cooperation gathering in San Francisco in...