[FileBrowser] Fixed tab navigation for detail-thumbnail-settings buttons.

chrome/browser/resources/file_manager/css/file_manager.css

Index: chrome/browser/resources/file_manager/css/file_manager.css
diff --git a/chrome/browser/resources/file_manager/css/file_manager.css b/chrome/browser/resources/file_manager/css/file_manager.css
index 3f58fd3b6ce8b8c43b734058f438957ba2aaa363..4178a56af49699ec41256d402a5ccfcb845e89a8 100644
--- a/chrome/browser/resources/file_manager/css/file_manager.css
+++ b/chrome/browser/resources/file_manager/css/file_manager.css
@@ -446,19 +446,12 @@ div.root-eject:hover {
   padding-left: 22px;
 }
 
-/* button:hover and button[disabled]:hover rules must be override by placing
- * the following four rules after them.
- */
-div.detail-view {
-  background-image: url('../images/icon_list_view.png');
-}
-
-div.thumbnail-view {
-  background-image: url('../images/icon_thumb_view.png');
-  margin-left: -1px;
+/* When detail-view is not disabled (thus thumbnail view is disabled), push
+   it up a little, to make it's right glowing border visible while focused.*/
+button#detail-view:not([disabled]) {
+  z-index: 2;
 }
 
-
 button.settings {
   display: none;
   /* Temporary solution not to uglify settings button */