Renamed app list position flag to --enable-centered-app-list.

ui/app_list/views/apps_container_view.cc

Index: ui/app_list/views/apps_container_view.cc
diff --git a/ui/app_list/views/apps_container_view.cc b/ui/app_list/views/apps_container_view.cc
index 8b612d8f20a48786c7f7ecbb178c1e697e593f8d..0a39ac24b3e4e11b615b715bbef361589c955689 100644
--- a/ui/app_list/views/apps_container_view.cc
+++ b/ui/app_list/views/apps_container_view.cc
@@ -30,7 +30,8 @@ AppsContainerView::AppsContainerView(AppListMainView* app_list_main_view,
   apps_grid_view_ = new AppsGridView(app_list_main_view, pagination_model);
   int cols = kPreferredCols;
   int rows = kPreferredRows;
-  if (app_list::switches::IsExperimentalAppListPositionEnabled()) {
+  // IsCenteredAppListEnabled also implies that it is wide instead of tall.
+  if (app_list::switches::IsCenteredAppListEnabled()) {
     cols = kExperimentalPreferredCols;
     rows = kExperimentalPreferredRows;
   }