We claim the ornamental design for a docking unit for computer, as shown and described.
FIG. 1 is a rear perspective view of a docking unit for computer of the present invention;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a first side view thereof;
FIG. 5 is a second side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a rear perspective view of the docking unit for computer in a closed position in which a portable computer in broken lines is provided to illustrate an example environment;
FIG. 9 is another rear perspective view of the docking unit for computer in an open position in which the portable computer in broken lines is provided to illustrate another example environment; and,
FIG. 10 is an exploded view thereof shown with the portable computer being detached.
The broken lines in the drawings represent environment that form no part of the claimed design.