c-lineup-ObjC-method-call is a compiled Lisp function in `cc-align.el'.

(c-lineup-ObjC-method-call LANGELEM)

Line up selector args as Emacs Lisp mode does with function args:
Go to the position right after the message receiver, and if you are at
the end of the line, indent the current line c-basic-offset columns
from the opening bracket; otherwise you are looking at the first
character of the first method call argument, so line up the current
line with it.

Works with: objc-method-call-cont.