revert "HLS seeking: call readAt() on new thread"

This reverts commit Ie527aeaff91e1b82c7e707a6feaf79548c7ac380

Bug: 119900000
Test: go/ag/5140159

Change-Id: Ia8b2f3efc2f3551e749c16c6c8dfbc070f8bb980
1 file changed