[MD settings] unit test for incognito activation

chrome/test/data/webui/settings/test_site_settings_prefs_browser_proxy.js

 // Copyright 2016 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.
 
 /**
  * An example empty pref.
  * @type {SiteSettingsPref}
  */
 var prefsEmpty = {
   defaults: {
@@ skipping 49 matching lines @@
     'removeCookie',
     'removeProtocolHandler',
     'removeUsbDevice',
     'removeZoomLevel',
     'resetCategoryPermissionForOrigin',
     'setCategoryPermissionForOrigin',
     'setDefaultValueForContentType',
     'setProtocolDefault'
   ]);
 
+  /** @private {boolean} */
+  this.hasIncognito = false;
+
   /** @private {!SiteSettingsPref} */
   this.prefs_ = prefsEmpty;
 
   /** @private {!Array<ZoomLevelEntry>} */
   this.zoomList_ = [];
 
   /** @private {!Array<!UsbDeviceEntry>} */
   this.usbDevices_ = [];
 
   /** @private {!Array<!ProtocolEntry>} */
   this.protocolHandlers_ = [];
 
   /** @private {?CookieList} */
   this.cookieDetails_ = null;
 
   /** @private {boolean} */
   this.isPatternValid_ = true;
 };
 
 TestSiteSettingsPrefsBrowserProxy.prototype = {
   __proto__: settings.TestBrowserProxy.prototype,
 
   /**
+   * Pretends an incognito session started or ended.
+   * @param {boolean} hasIncognito True for session started.
+   */
+  setIncognito: function(hasIncognito) {
+    this.hasIncognito = hasIncognito;
+    cr.webUIListenerCallback('onIncognitoStatusChanged', hasIncognito);
+  },
+
+  /**
    * Sets the prefs to use when testing.
    * @param {!SiteSettingsPref} prefs The prefs to set.
    */
   setPrefs: function(prefs) {
     this.prefs_ = prefs;
 
     // Notify all listeners that their data may be out of date.
     for (var type in settings.ContentSettingsTypes) {
       cr.webUIListenerCallback(
           'contentSettingSitePermissionChanged',
@@ skipping 121 matching lines @@
     else if (contentType == settings.ContentSettingsTypes.PROTECTED_CONTENT)
       pref = this.prefs_.exceptions.protectedContent;
     else if (contentType == settings.ContentSettingsTypes.POPUPS)
       pref = this.prefs_.exceptions.popups;
     else if (contentType == settings.ContentSettingsTypes.UNSANDBOXED_PLUGINS)
       pref = this.prefs_.exceptions.unsandboxed_plugins;
     else
       console.log('getExceptionList received unknown category: ' + contentType);
 
     assert(pref != undefined, 'Pref is missing for ' + contentType);
+
+    if (this.hasIncognito) {
+      pref = pref.concat(pref.filter(function(p) {

[dpapad, 2017/03/23 22:29:10]

I am confused about the usage of filter() here. filter() is expected to return
either true or false to signify what stays and what is dropped. Here we are
returning either an Object or undefined. Should it simply be 

pref = pref.concat(pref.filter(function(p) { return p.source == 'policy'; }));

[dschuyler, 2017/03/23 23:54:36]

filter() returns the object returned by the function.

I've changed this to a loop so that the incognito flag is set correctly.

+        if (p.source == 'policy')
+          return Object.assign({incognito: true}, p);
+      }));
+    }
+
     return Promise.resolve(pref);
   },
 
   /** @override */
   isPatternValid: function(pattern) {
     this.methodCalled('isPatternValid', pattern);
     return Promise.resolve(this.isPatternValid_);
   },
 
   /**
@@ skipping 67 matching lines @@
   /** @override */
   setProtocolDefault: function() {
     this.methodCalled('setProtocolDefault', arguments);
   },
 
   /** @override */
   removeProtocolHandler: function() {
     this.methodCalled('removeProtocolHandler', arguments);
   }
 };