The ornamental design for a casing for electronicdevice, as shown and described.
FIG. 1 is a perspective view of the casing for electronic device;
FIG. 2 is a front elevational view of the embodiment of the design, the rear elevational view being identical;
FIG. 3 is a left side elevational view of the embodiment of the design, the right side elevational view being identical;
FIG. 4 is a top plan view of the embodiment of the design;
FIG. 5 is a bottom plan view of the embodiment of the design; and,
FIG. 6 is an enlarged fragmented view of the embodiment of the design as indicated in FIG. 2.
The broken lines are included in the drawings to show unclaimed subject matter only and form no part of the claimed design. The gray shown on the cover in FIGS. 1-6 represents a thin film.