App Launcher: Preload the correct number of icons (don't assume 4x4).

ui/app_list/views/apps_grid_view.h

Index: ui/app_list/views/apps_grid_view.h
diff --git a/ui/app_list/views/apps_grid_view.h b/ui/app_list/views/apps_grid_view.h
index c6c9efa6f800626ace779214e5aa5590cacb5a5d..8ae31176729a61c88c7c050d56c1df6314371587 100644
--- a/ui/app_list/views/apps_grid_view.h
+++ b/ui/app_list/views/apps_grid_view.h
@@ -80,8 +80,8 @@ class APP_LIST_EXPORT AppsGridView : public views::View,
   // is no longer called to dynamically choosing those layout params.
   void SetLayout(int icon_size, int cols, int rows_per_page);
 
-  int cols() { return cols_; }
-  int rows_per_page() { return rows_per_page_; }
+  int cols() const { return cols_; }
+  int rows_per_page() const { return rows_per_page_; }
 
   // This resets the grid view to a fresh state for showing the app list.
   void ResetForShowApps();