Friday in the Bay Area saw something unusual: Not a drop in housing prices, or a win from the San Francisco Giants. But rain in June. A cold front blustering in from the Pacific Ocean off the Washington and Oregon coast brought gray skies and the first measurable rainfall on Thursday and Friday to the Bay Area’s three biggest cities — San Jose, San Francisco and Oakland — since April 20. And although it sent windshield wipers moving and people digging out raincoats from the backs of their closets, the storm didn’t bring much rain.