Added more typechecking functions and unit tests for existing code.

remoting/webapp/crd/js/client_plugin_host_desktop_impl.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview
  * Provides an interface to manage the Host Desktop of a remoting session.
  */
 
 var remoting = remoting || {};
@@ skipping 68 matching lines @@
 };
 
 /**
  * This function is called by |this.plugin_| when the size of the host
  * desktop is changed.
  *
  * @param {remoting.ClientPluginMessage} message
  */
 remoting.ClientPlugin.HostDesktopImpl.prototype.onSizeUpdated = function(
     message) {
-  this.width_ = getNumberAttr(message.data, 'width');
-  this.height_ = getNumberAttr(message.data, 'height');
-  this.xDpi_ = getNumberAttr(message.data, 'x_dpi', 96);
-  this.yDpi_ = getNumberAttr(message.data, 'y_dpi', 96);
+  this.width_ = base.getNumberAttr(message.data, 'width');
+  this.height_ = base.getNumberAttr(message.data, 'height');
+  this.xDpi_ = base.getNumberAttr(message.data, 'x_dpi', 96);
+  this.yDpi_ = base.getNumberAttr(message.data, 'y_dpi', 96);
   this.raiseEvent(remoting.HostDesktop.Events.sizeChanged,
                   this.getDimensions());
 };
 
 /**
  * This function is called by |this.plugin_| when the shape of the host
  * desktop is changed.
  *
  * @param {remoting.ClientPluginMessage} message
  * @return {Array<{left:number, top:number, width:number, height:number}>}
  *    rectangles of the desktop shape.
  */
 remoting.ClientPlugin.HostDesktopImpl.prototype.onShapeUpdated =
     function(message) {
-  var shapes = getArrayAttr(message.data, 'rects');
+  var shapes = base.getArrayAttr(message.data, 'rects');
   var rects = shapes.map(
     /** @param {Array.<number>} shape */
     function(shape) {
       if (!Array.isArray(shape) || shape.length != 4) {
         throw 'Received invalid onDesktopShape message';
       }
       var rect = {};
       rect.left = shape[0];
       rect.top = shape[1];
       rect.width = shape[2];
       rect.height = shape[3];
       return rect;
   });
 
   this.raiseEvent(remoting.HostDesktop.Events.shapeChanged, rects);
   return rects;
 };
 
 }());