Introduce Image loader extension.

chrome/browser/resources/file_manager/js/action_choice.js

 // Copyright (c) 2012 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.
 
 document.addEventListener('DOMContentLoaded', function() {
   ActionChoice.load();
 });
 
 /**
  * The main ActionChoice object.
@@ skipping 202 matching lines @@
     } else {
       this.renderPreview_(entries, count);
     }
   }.bind(this);
 
   this.metadataCache_.get(entry, 'thumbnail|filesystem',
       function(metadata) {
         new ThumbnailLoader(entry.toURL(),
                             ThumbnailLoader.LoaderType.IMAGE,
                             metadata).load(
-            box, ThumbnailLoader.FillMode.FILL, onSuccess, onError, onError);
+            box,
+            ThumbnailLoader.OptimizationMode.DISCARD_DETACHED,
+            ThumbnailLoader.FillMode.FILL,
+            onSuccess,
+            onError,
+            onError);
       });
 };
 
 /**
  * Closes the window.
  * @private
  */
 ActionChoice.prototype.close_ = function() {
   window.close();
 };
@@ skipping 80 matching lines @@
  */
 ActionChoice.prototype.recordAction_ = function(action) {
   metrics.recordEnum('PhotoImport.Action', action,
       ['import-photos-to-drive',
        'view-files',
        'view-files-auto',
        'watch-single-video',
        'error',
        'close']);
 };