Gallery: make file name field not to overlap on edit button.

ui/file_manager/gallery/css/gallery.css

 /* Copyright (c) 2014 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
 body {
   -webkit-user-select: none;
   font-size: 84%;
   margin: 0;
 }
 
@@ skipping 373 matching lines @@
   flex-direction: column;
 }
 
 /* Toolbar buttons */
 
 .gallery .button-spacer {
   align-items: center;
   display: flex;
   flex: none;
   justify-content: flex-end;
-  width: 252px; /* 42px button x 6 */
 }
 
 /* Thumbnails */
 
 .gallery .ribbon-spacer {
   height: 55px;
   position: relative;
 }
 
 .gallery .toolbar .ribbon {
@@ skipping 1073 matching lines @@
 .thumbnail-view .animation-thumbnail {
   background-repeat: no-repeat;
   background-size: cover;
   display: none;
   position: absolute;
 }
 
 .thumbnail-view .animation-thumbnail.animating {
   display: block;
 }