By WILL WEISSERT and COLLIN BINKLEYWASHINGTON (AP) — President Donald Trump played White House tour guide on Wednesday, showing off the helipad he is building on the lawn before leaning over to autograph a piece of it and bragging about the ballroom he’s rushing to complete despite legal challenges. Trump gushed for several uninterrupted minutes about granite being laid and said the chopper landing area would leave visiting foreign leaders “very impressed” — including Chinese President Xi Jinping, who is coming next month. [embedded content] At times, he sounded almost like a construction manager, singing the praises of granite over...