The ornamental design for a mirrorbasecover, as shown and described.
FIG. 1 is a perspective view of the mirror base cover in accordance with our new design;
FIG. 2 is a front view of the mirror base cover of FIG. 1;
FIG. 3 is a top view of the mirror base cover of FIG. 1;
FIG. 4 is a bottom view of the mirror base cover of FIG. 1;
FIG. 5 is a left side view of the mirror base cover of FIG. 1; and,
FIG. 6 is a right side view of mirror base cover of FIG. 2.
FIGS. 1-6 illustrate a first embodiment of our novel design suitable for use on the left side of a vehicle. Our novel design also includes a second embodiment suitable for use on the right side of a vehicle, which is mirror symmetrical to FIGS. 1-6 and therefore not separately illustrated.
The broken lines immediately adjacent the shaded areas as depicted in the FIGURES, represent the bounds of the claimed design while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.