I claim the ornamental design for a can support frame, as shown and described.
FIG. 1 is a right side perspective view of the can support frame
FIG. 2 is a left side perspective view thereof.
FIG. 3 is a right side elevation view thereof.
FIG. 4 is a top plan view thereof.
FIG. 5 is a bottom plan view thereof.
FIG. 6 is a front elevation view thereof.
FIG. 7 is a rear elevation view thereof.
FIG. 8 is a left side elevation view thereof; and,
FIG. 9 is a perspective view showing the can support frame and the broken line portions shown illustrate environmental subject matter only and form no part of the claimed design.