I claim the ornamental design for a shower controller, as shown and described.
FIG. 1 is a perspective view of an embodiment of the claimed design;
FIG. 2 is another perspective view of the design shown in FIG. 1;
FIG. 3 is a front view of the design shown in FIG. 1; and,
FIG. 4 is a side view of the design shown in FIG. 1.
The ornamental design which is claimed is shown in solid lines in the drawings: The broken lines formed by shorter length dash-dash lines illustrate unclaimed portions of the design. The broken lines formed by longer length dash-dash lines illustrate illumination and/or lighting only and form no part of the claimed design. Broken lines formed by dash-dot lines show boundaries between claimed and unclaimed portions of the design. The oblique line shading illustrates transparency or translucency.