The ornamental design for a frontportion of an automobile, as shown and described.
FIG. 1 is a front and right front perspective view of a front portion of an automobile of our new design;
FIG. 2 is a rear and right side perspective thereof;
FIG. 3 is a right side elevation view thereof, the left side being a mirror image thereof;
FIG. 4 is a front elevation view thereof;
FIG. 5 is a rear elevation view thereof; and,
FIG. 6 is a top plan view thereof.
The portion of the vehicle in light contrast is environment and is not a part of the claimed design. The bottom view of the front portion of the automobile forms no part of the claimed design.