Avoid UI unresponsiveness when switching between large images.

ui/file_manager/gallery/js/image_editor/image_view.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.
 
 /**
  * The overlay displaying the image.
  *
  * @param {!HTMLElement} container The container element.
  * @param {!Viewport} viewport The viewport.
  * @param {!MetadataModel} metadataModel
@@ skipping 120 matching lines @@
 };
 
 /**
  * Obtains prefered load type from GalleryItem.
  *
  * @param {!GalleryItem} item
  * @param {!ImageView.Effect} effect
  * @return {ImageView.LoadTarget} Load target.
  */
 ImageView.getLoadTarget = function(item, effect) {
-  if (item.contentImage)
+  if (item.contentImage && !item.requireLongRenderingTime())
     return ImageView.LoadTarget.CACHED_MAIN_IMAGE;
 
   // Only show thumbnails if there is no effect or the effect is Slide or
   // ZoomToScreen.
   var thumbnailLoader = new ThumbnailLoader(
       item.getEntry(),
       ThumbnailLoader.LoaderType.CANVAS,
       item.getThumbnailMetadataItem());
   if ((effect instanceof ImageView.Effect.None ||
        effect instanceof ImageView.Effect.Slide ||
@@ skipping 814 matching lines @@
 
 ImageView.Effect.Rotate.prototype = { __proto__: ImageView.Effect.prototype };
 
 /**
  * @override
  */
 ImageView.Effect.Rotate.prototype.transform = function(element, viewport) {
   return viewport.getRotatingTransformation(
       element.width, element.height, this.orientation_ ? -1 : 1);
 };