[MD settings] unit test for incognito activation

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

Index: chrome/test/data/webui/settings/test_site_settings_prefs_browser_proxy.js
diff --git a/chrome/test/data/webui/settings/test_site_settings_prefs_browser_proxy.js b/chrome/test/data/webui/settings/test_site_settings_prefs_browser_proxy.js
index 6fe9b1ca4a670e19f9e30d280c432135acc73109..ef7069b910a07af76810c9ecb0700fe7e5603a57 100644
--- a/chrome/test/data/webui/settings/test_site_settings_prefs_browser_proxy.js
+++ b/chrome/test/data/webui/settings/test_site_settings_prefs_browser_proxy.js
@@ -67,6 +67,9 @@ var TestSiteSettingsPrefsBrowserProxy = function() {
     'setProtocolDefault'
   ]);
 
+  /** @private {boolean} */
+  this.hasIncognito = false;
+
   /** @private {!SiteSettingsPref} */
   this.prefs_ = prefsEmpty;
 
@@ -90,6 +93,15 @@ 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.
    */
@@ -231,6 +243,14 @@ TestSiteSettingsPrefsBrowserProxy.prototype = {
       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) {
+        if (p.source == 'policy')
+          return Object.assign({incognito: true}, p);
+      }));
+    }
+
     return Promise.resolve(pref);
   },