Gallery: Disable name input when the selection is empty.

ui/file_manager/gallery/js/gallery.js

 // Copyright 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.
 
 'use strict';
 
 /**
  * Called from the main frame when unloading.
  * @param {boolean=} opt_exiting True if the app is exiting.
  */
@@ skipping 852 matching lines @@
       } else {
         document.title = '';
       }
       this.filenameEdit_.disabled = true;
       this.filenameEdit_.value =
           strf('GALLERY_ITEMS_SELECTED', numSelectedItems);
       this.shareButton_.hidden = true;
     }
   } else {
     document.title = '';
+    this.filenameEdit_.disabled = true;
     this.filenameEdit_.value = '';
     this.shareButton_.hidden = true;
   }
 
   util.updateAppState(
       null,  // Keep the current directory.
       selectedEntryURL,  // Update the selection.
       {gallery: (this.currentMode_ === this.mosaicMode_ ? 'mosaic' : 'slide')});
 };
 
@@ skipping 132 matching lines @@
   window.loadTimeData.data = backgroundComponents.stringData;
   gallery = new Gallery(backgroundComponents.volumeManager);
 };
 
 /**
  * Loads entries.
  */
 window.loadEntries = function(entries, selectedEntries) {
   gallery.load(entries, selectedEntries);
 };