What are the helicopter frequencies on the LA heli charts used for?
This is the frequency for the tower controller who is due to control inbound helicopters. You can see LAX 119.8, HHR 121.1 and LGB 120.5 frequencies noted. These are all frequencies used by the tower controller at these aerodromes. 

At LAX, the class bravo transition will be issued by the tower controller on 119.8.