WASHINGTON (Reuters) - The U.S. Supreme Court agreed on Friday to decide whether police can search an arrested criminal suspect's cell phone without a warrant in two cases that showcase how the courts are wrestling to keep up with rapid technological advances. Taking up cases from California and Massachusetts arising from criminal prosecutions that used evidence obtained without a warrant, the high court will wade into how to apply older court precedent, which allows police to search items carried by a defendant at the time of arrest, to cell phones.