Remove unused ash::SHELF_ALIGNMENT_TOP

ash/shelf/shelf_layout_manager.h

Index: ash/shelf/shelf_layout_manager.h
diff --git a/ash/shelf/shelf_layout_manager.h b/ash/shelf/shelf_layout_manager.h
index 6c9bff965d5cc7e0d5cfaeb2ba58349062aae42f..7628b1340b4cd900670579955ef0de72fe5a3c83 100644
--- a/ash/shelf/shelf_layout_manager.h
+++ b/ash/shelf/shelf_layout_manager.h
@@ -185,8 +185,8 @@ class ASH_EXPORT ShelfLayoutManager
   // new Shelf class.
   // A helper function that provides a shortcut for choosing
   // values specific to a shelf alignment.
-  template<typename T>
-  T SelectValueForShelfAlignment(T bottom, T left, T right, T top) const {
+  template <typename T>
+  T SelectValueForShelfAlignment(T bottom, T left, T right) const {
     switch (GetAlignment()) {
       case SHELF_ALIGNMENT_BOTTOM:
         return bottom;
@@ -194,8 +194,6 @@ class ASH_EXPORT ShelfLayoutManager
         return left;
       case SHELF_ALIGNMENT_RIGHT:
         return right;
-      case SHELF_ALIGNMENT_TOP:
-        return top;
     }
     NOTREACHED();
     return right;