I claim the ornamental design for a glass shade, as shown and described.
FIG. 1 is a perspective view of a glass shade showing my new design;
FIG. 2 is a front elevational view of the glass shade, the rear elevational
view being identical and the left and right side elevational views being a
mirror image;
FIG. 3 is a top plan view of the glass shade; and,
FIG. 4 is a bottom plan view of the glass shade.
The broken lines shown are for illustrative purposes only and form no part
of the claimed design.