FIG. 1 is a front view of my new and ornamental design for a watch case;

FIG. 2 is a back view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right front perspective view thereof.