Gallery: change size of crop overlay to cover entire window.

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 834 matching lines @@
   background-image: -webkit-image-set(
       url(../images/100/contrast.png) 1x,
       url(../images/200/contrast.png) 2x);
 }
 
 /* Crop frame */
 
 .gallery .crop-overlay {
   -webkit-box-orient: vertical;
   display: -webkit-box;
+  height: 100%;
   pointer-events: none;
   position: absolute;
+  width: 100%;
 }
 
 .gallery .crop-overlay .shadow {
   background-color: rgba(0, 0, 0, 0.65);
 }
 
 .gallery .crop-overlay .middle-box {
   -webkit-box-flex: 1;
   -webkit-box-orient: horizontal;
   display: -webkit-box;
@@ skipping 515 matching lines @@
 .thumbnail-view .animation-thumbnail {
   background-repeat: no-repeat;
   background-size: cover;
   display: none;
   position: absolute;
 }
 
 .thumbnail-view .animation-thumbnail.animating {
   display: block;
 }