U.S. officials and some outside experts say they expect this week’s meeting between President Trump and Chinese President Xi Jinping to head off an escalating trade war and restart trade negotiations between the world’s two largest economic powers. The two leaders are scheduled to meet on the sidelines of the June 28 and 29 G20 economic summit in Osaka, Japan, amid signs that both sides are eager to forestall an escalating round of tariffs that is pushing China deeper into debt and prompting U.S.