The Walt Disney Co. has submitted plans to the city of Burbank for a new 10-story building — with the ABC logo displayed prominently atop. The news is once again fueling speculation that Disney will move the network headquarters to the Valley and vacate its Century City offices, which it leases. The 380,000-square-foot building would go up at Riverside Drive and Buena Vista Street, near the studio’s current animation facility. There was much talk that ABC would be moved to Burbank at the time of the merger in the summer of 1995. Disney and ABC each had no comment.