[MD settings] make About menu item blue when selected

chrome/browser/resources/settings/settings_menu/settings_menu.js

Index: chrome/browser/resources/settings/settings_menu/settings_menu.js
diff --git a/chrome/browser/resources/settings/settings_menu/settings_menu.js b/chrome/browser/resources/settings/settings_menu/settings_menu.js
index dd66609cf9564896c5e422e4788bccdc9ef29f9f..29d51ad9a343ed87858f227cd18ef48af1765f1c 100644
--- a/chrome/browser/resources/settings/settings_menu/settings_menu.js
+++ b/chrome/browser/resources/settings/settings_menu/settings_menu.js
@@ -9,9 +9,11 @@
 Polymer({
   is: 'settings-menu',
 
+  behaviors: [settings.RouteObserverBehavior],
+
   properties: {
     /** @private */
-    advancedOpened_: Boolean,

[Dan Beam, 2016/10/14 00:09:09]

this is still referenced from the HTML, but no longer exists... :(

+    aboutSelected_: Boolean,
 
     /**
      * Dictionary defining page visibility.
@@ -43,6 +45,28 @@ Polymer({
   },
 
   /**
+   * @param {!settings.Route} newRoute
+   */
+  currentRouteChanged: function(newRoute) {
+    // Make the three menus mutually exclusive.
+    if (settings.Route.ABOUT.contains(newRoute)) {
+      this.aboutSelected_ = true;
+      this.$.advancedMenu.selected = null;
+      this.$.basicMenu.selected = null;
+    } else if (settings.Route.ADVANCED.contains(newRoute)) {
+      this.aboutSelected_ = false;
+      // For routes from URL entry, we need to set selected.
+      this.$.advancedMenu.selected = newRoute.path;
+      this.$.basicMenu.selected = null;
+    } else if (settings.Route.BASIC.contains(newRoute)) {
+      this.aboutSelected_ = false;
+      this.$.advancedMenu.selected = null;
+      // For routes from URL entry, we need to set selected.
+      this.$.basicMenu.selected = newRoute.path;
+    }
+  },
+
+  /**
    * @param {!Event} event
    * @private
    */