The ornamental design for a barrierbase, as shown and described.
FIG. 1 is a front view of the barrier base showing our new design;
FIG. 2 is an enlarged front view of the barrier base of FIG. 1 showing our new design;
FIG. 3 is a bottom perspective view thereof showing an opening to a void within the barrier base;
FIG. 4 is a front perspective view thereof;
FIG. 5 is a first side view thereof;
FIG. 6 is a rear view thereof; and,
FIG. 7 is a second side view thereof.
The broken line showing of the upper portion of a barrier in FIGS. 1-7 is included for the purpose of illustrating environmental structure only and form no part of the claimed design. The four small circular broken lines on the surface of the barrier base in FIGS. 3 and 4 represent portions of the barrier base that form no part of the claimed invention.