Gallery: Add animation when zooming pictures.

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.
 
 'use strict';
 
 /**
  * The overlay displaying the image.
  *
  * @param {HTMLElement} container The container element.
@@ skipping 108 matching lines @@
     this.displayedContentGeneration_ = this.contentGeneration_;
 
     ImageUtil.trace.resetTimer('paint');
     this.paintDeviceRect(this.viewport_.getDeviceClipped(),
         this.contentCanvas_, this.viewport_.getImageClipped());
     ImageUtil.trace.reportTimer('paint');
   }
 };
 
 /**
+ * Applies the viewport change that does not affect the screen cache size (zoom
+ * change or offset change) with animation.
+ */
+ImageView.prototype.applyViewportChange = function() {
+  this.setTransform(
+      this.screenImage_,
+      new ImageView.Effect.None(),
+      ImageView.Effect.DEFAULT_DURATION);
+};
+
+/**
  * @return {number} The cache generation.
  */
 ImageView.prototype.getCacheGeneration = function() {
   return this.contentGeneration_;
 };
 
 /**
  * Invalidates the caches to force redrawing the screen canvas.
  */
 ImageView.prototype.invalidateCaches = function() {
@@ skipping 812 matching lines @@
 };
 
 ImageView.Effect.Rotate.prototype = { __proto__: ImageView.Effect.prototype };
 
 /**
  * @override
  */
 ImageView.Effect.Rotate.prototype.transform = function(element, viewport) {
   return viewport.getInverseTransformForRotatedImage(this.orientation_);
 };