[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..4ac5821ca2776efe76f883eec67c6476f4967823 100644
--- a/chrome/browser/resources/settings/settings_menu/settings_menu.js
+++ b/chrome/browser/resources/settings/settings_menu/settings_menu.js
@@ -9,8 +9,13 @@
 Polymer({
   is: 'settings-menu',
 
+  behaviors: [settings.RouteObserverBehavior],
+
   properties: {
     /** @private */
+    aboutSelected_: Boolean,
+
+    /** @private */
     advancedOpened_: Boolean,

[tommycli, 2016/08/22 23:23:00]

I think you can axe this property declaration, since it's not used by any of the
method bodies below.

[dschuyler, 2016/08/22 23:35:09]

Done.

 
     /**
@@ -43,6 +48,28 @@ Polymer({
   },
 
   /**
+   * Handle setting selected menu item from URL routes as well as menu
+   * selections.

[tommycli, 2016/08/22 23:23:00]

nit: clarify comment to something like:

Update menus based on new route.

Or just remove comment.

[dschuyler, 2016/08/22 23:35:09]

I wanted to point out that some of the code
is important for URLs entered in in the omnibox.
I removed the top comment and added more specific
comments.

[tommycli, 2016/08/22 23:36:58]

Thanks. New comments helpful. This is a subtle piece

+   * @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;
+      this.$.advancedMenu.selected = newRoute.path;
+      this.$.basicMenu.selected = null;
+    } else if (settings.Route.BASIC.contains(newRoute)) {
+      this.aboutSelected_ = false;
+      this.$.advancedMenu.selected = null;
+      this.$.basicMenu.selected = newRoute.path;
+    }
+  },
+
+  /**
    * @param {!Event} event
    * @private
    */