WASHINGTON (Reuters) - U.S. President Donald Trump will meet April 6-7 with Chinese President Xi Jinping at the president’s Mar-a-Lago retreat in Florida, a source familiar with the meeting said on Tuesday. It will be their first face-to-face meeting since Trump took office on Jan. 20. Trump played host to Japanese Prime Minister Shinzo Abe last month at Mar-a-Lago, in Palm Beach, Florida. 