I claim the ornamental design for a tray liner, as shown and described.
FIG. 1 is a top perspective view of a tray liner showing my new design;
FIG. 2 is a front elevational view of FIG. 1;
FIG. 3 is a rear elevational view of FIG. 1;
FIG. 4 is a left-side elevational view of FIG. 1;
FIG. 5 is a right-side elevational view of FIG. 1;
FIG. 6 is a top plan view of FIG. 1;
FIG. 7 is a bottom plan view of FIG. 1; and,
FIG. 8 is a bottom perspective view of FIG. 1.
The broken away symbols in the drawings indicate the appearance of any portion of the article between the break lines forms no part of the claimed design.