Make the Viewport class pure model.

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
  */
 function Viewport() {
   this.imageBounds_ = new Rect();
   this.screenBounds_ = new Rect();
 
   this.scale_ = 1;
   this.offsetX_ = 0;
   this.offsetY_ = 0;
 
   this.generation_ = 0;
 
-  this.scaleControl_ = null;
   this.repaintCallbacks_ = [];
   this.update();
 }
 
 /*
  * Viewport modification.
  */
 
 /**
- * @param {Object} scaleControl The UI object responsible for scaling.
- */
-Viewport.prototype.setScaleControl = function(scaleControl) {
-  this.scaleControl_ = scaleControl;
-};
-
-/**
  * @param {number} width Image width.
  * @param {number} height Image height.
  */
 Viewport.prototype.setImageSize = function(width, height) {
   this.imageBounds_ = new Rect(width, height);
-  if (this.scaleControl_) this.scaleControl_.displayImageSize(width, height);
   this.invalidateCaches();
 };
 
 /**
  * @param {number} width Screen width.
  * @param {number} height Screen height.
  */
 Viewport.prototype.setScreenSize = function(width, height) {
   this.screenBounds_ = new Rect(width, height);
-  if (this.scaleControl_)
-    this.scaleControl_.setMinScale(this.getFittingScale());
   this.invalidateCaches();
 };
 
 /**
  * Set the size by an HTML element.
  *
  * @param {HTMLElement} frame The element acting as the "screen".
  */
 Viewport.prototype.sizeByFrame = function(frame) {
   this.setScreenSize(frame.clientWidth, frame.clientHeight);
@@ skipping 18 matching lines @@
  */
 Viewport.prototype.getScale = function() { return this.scale_; };
 
 /**
  * @param {number} scale The new scale.
  * @param {boolean} notify True if the change should be reflected in the UI.
  */
 Viewport.prototype.setScale = function(scale, notify) {
   if (this.scale_ == scale) return;
   this.scale_ = scale;
-  if (notify && this.scaleControl_) this.scaleControl_.displayScale(scale);
   this.invalidateCaches();
 };
 
 /**
  * @return {number} Best scale to fit the current image into the current screen.
  */
 Viewport.prototype.getFittingScale = function() {
   var scaleX = this.screenBounds_.width / this.imageBounds_.width;
   var scaleY = this.screenBounds_.height / this.imageBounds_.height;
   // Scales > (1 / this.getDevicePixelRatio()) do not look good. Also they are
   // not really useful as we do not have any pixel-level operations.
   return Math.min(1 / Viewport.getDevicePixelRatio(), scaleX, scaleY);
 };
 
 /**
  * Set the scale to fit the image into the screen.
  */
 Viewport.prototype.fitImage = function() {
   var scale = this.getFittingScale();
-  if (this.scaleControl_) this.scaleControl_.setMinScale(scale);
   this.setScale(scale, true);
 };
 
 /**
  * @return {number} X-offset of the viewport.
  */
 Viewport.prototype.getOffsetX = function() { return this.offsetX_; };
 
 /**
  * @return {number} Y-offset of the viewport.
@@ skipping 299 matching lines @@
 };
 
 /**
  * Repaint all clients.
  */
 Viewport.prototype.repaint = function() {
   this.update();
   for (var i = 0; i != this.repaintCallbacks_.length; i++)
     this.repaintCallbacks_[i]();
 };