Gallery: Add animation when zooming pictures.

ui/file_manager/gallery/js/slide_mode.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';
 
 /**
  * Slide mode displays a single image and has a set of controls to navigate
  * between the images and to edit an image.
  *
@@ skipping 851 matching lines @@
     case 'Left':
     case 'Right':
     case 'MediaNextTrack':
     case 'MediaPreviousTrack':
       this.advanceWithKeyboard(keyID);
       break;
 
     case 'Ctrl-U+00BB':  // Ctrl+'=' zoom in.
       if (!this.isEditing()) {
         this.viewport_.setZoomIndex(this.viewport_.getZoomIndex() + 1);
-        this.imageView_.draw();
+        this.imageView_.applyViewportChange();
       }
       break;
 
     case 'Ctrl-U+00BD':  // Ctrl+'-' zoom out.
       if (!this.isEditing()) {
         this.viewport_.setZoomIndex(this.viewport_.getZoomIndex() - 1);
-        this.imageView_.draw();
+        this.imageView_.applyViewportChange();
       }
       break;
   }
 
   return true;
 };
 
 /**
  * Resize handler.
  * @private
@@ skipping 402 matching lines @@
       done = true;
     }
   }.bind(this);
 };
 
 /**
  * If the user touched the image and moved the finger more than SWIPE_THRESHOLD
  * horizontally it's considered as a swipe gesture (change the current image).
  */
 SwipeOverlay.SWIPE_THRESHOLD = 100;