[filebrowser] Support renaming in Gallery.

chrome/browser/resources/file_manager/js/image_editor/gallery.css

 /*
  * Copyright (c) 2011 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 {
   margin: 0;
   -webkit-user-select: none;
   font-family: Open Sans,Droid Sans Fallback,sans-serif;
@@ skipping 208 matching lines @@
  of the crop frame */
 .gallery[tools][editing] *[dimmed],
 .gallery[tools][editing] *[dimmed] * {
   pointer-events: none;
 }
 
 .gallery[tools][editing] *[dimmed] {
   opacity: 0.2;
 }
 
+/* Filename */
+
+.gallery .filename-spacer {
+  padding: 0 10px;
+  display: -webkit-box;
+  -webkit-box-orient: horizontal;
+  -webkit-box-align: center;
+}
+
+.gallery .filename-spacer > input {
+  background-color: transparent;
+  color: white;
+  width: 40em;
+  border: none;
+  outline: none;
+}
+
+.gallery .filename-spacer > input:focus {
+  background-color: rgba(48, 48, 48, 0.75);
+  border-right: 1px solid white;
+  border-bottom: 1px solid white;
+}
+
 /* Thumbnails */
 
 .gallery .ribbon-spacer {
   position: relative;
   display: -webkit-box;
   -webkit-box-flex: 1;
   -webkit-box-orient: horizontal;
 }
 
 .gallery .toolbar .ribbon {
@@ skipping 465 matching lines @@
 }
 
 .gallery .share-menu > div:hover {
   background-color: rgba(240,240,240,1);
 }
 
 .gallery .share-menu > div > img {
   margin-right: 5px;
   display: block;
 }