Gallery: Add animation when zooming pictures.

ui/file_manager/gallery/js/image_editor/viewport.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';
 
 /**
  * Viewport class controls the way the image is displayed (scale, offset etc).
  * @constructor
  */
@@ skipping 80 matching lines @@
  * Sets the new zoom ratio.
  * @param {number} zoomIndex New zoom index.
  */
 Viewport.prototype.setZoomIndex = function(zoomIndex) {
   // Ignore the invalid zoomIndex.
   if (!Viewport.ZOOM_RATIOS[zoomIndex.toString()])
     return;
 
   this.zoomIndex_ = zoomIndex;
   this.zoom_ = Viewport.ZOOM_RATIOS[zoomIndex];
-  this.invalidateCaches();
 };
 
 /**
  * Returns the current zoom index.
  * @return {number} Zoon index.
  */
 Viewport.prototype.getZoomIndex = function() {
   return this.zoomIndex_;
 };
 
@@ skipping 408 matching lines @@
   var screenWidth = this.screenBounds_.width;
   var screenHeight = this.screenBounds_.height;
   var dx = screenRect.left + screenRect.width / 2 - screenWidth / 2;
   var dy = screenRect.top + screenRect.height / 2 - screenHeight / 2;
   return [
     'translate(' + dx + 'px,' + dy + 'px)',
     'scale(' + scaleX + ',' + scaleY + ')',
     this.getTransformation()
   ].join(' ');
 };