The ornamental design for infant chair, as shown and described.
FIG. 1 is a top, left, front perspective view of an infant chair showing my new design;
FIG. 2 is a front elevational view of the infant chair shown in FIG. 1;
FIG. 3 is a rear elevational view of the infant chair shown in FIG. 1;
FIG. 4 is a right side elevational view of the infant chair shown in FIG. 1;
FIG. 5 is a left side elevational view of the infant chair shown in FIG. 1;
FIG. 6 is a top plan view of the infant chair shown in FIG. 1; and,
FIG. 7 is a bottom plan view of the infant chair shown in FIG. 1.
The broken line showing of portions of the infant chair is included for the purpose of illustrating environmental structure and forms no part of the claimed design.