FIG. 1 is a front plan view of a high chair liner showing my new design;

FIG. 2 is a rear plan view thereof;

FIG. 3 is a left side elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a top left side perspective view thereof shown open;

FIG. 8 is a perspective view of a high chair liner of FIGS. 1-7 folded up showing my new design; and,

FIG. 9 is a top left side perspective view of the high chair liner shown in FIGS. 1-7 on a high chair with a top portion folded over, the broken line disclosure of a high chair being for illustrating purposes only and forming no part of the claimed design.