We claim the ornamental design for a case for electronic device, as shown and described.
FIG. 1 is a front perspective view of a case for electronic device showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left-side view thereof;
FIG. 5 is a right-side view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a open perspective view thereof; and,
FIG. 9 is an open rear perspective view thereof.
The broken lines immediately adjacent the shaded surfaces represent boundaries of the claimed design. All other broken lines depict unclaimed environment and form no part of the claimed design.