City’s new landmarks are struggling office buildings and a shopping mall losing tenants.. As it rolls toward downtown San Francisco, the California Street cable car passes the gothic Grace Cathedral and an 8-foot tall statue of Tony Bennett. Then riders start to see the city’s newest landmarks. Among them is 650 California Street, a 34-story office building that has defaulted on its mortgage. Further on is 101 California, whose second-biggest tenant left last year and whose biggest is slashing staff and office space. Go around the corner, and Embarcadero Square is for sale for $90 million. Its owner bought it...