The ornamental design for a watchcase, as shown and described.
FIG. 1 is a top perspective view of a watch case;
FIG. 2 is a bottom, perspective view of the watch case;
FIG. 3 is a top plan view of the watch case;
FIG. 4 is a bottom plan view of the watch case;
FIG. 5 is a first side elevational view of the watch case looking towards the nine o'clock position;
FIG. 6 is a second side elevational view of the watch case looking towards the three o'clock position; and,
FIG. 7 is a third side elevational view of the watch case looking towards the six o'clock position, with the fourth side elevational view looking towards the twelve o'clock position being a mirror image thereof.
The broken lines are included for the purpose of portions of the watch case and form no part of the claimed design.