MD Settings: Remove some unhelpful properties

chrome/browser/resources/settings/settings_page/main_page_behavior.js

Index: chrome/browser/resources/settings/settings_page/main_page_behavior.js
diff --git a/chrome/browser/resources/settings/settings_page/main_page_behavior.js b/chrome/browser/resources/settings/settings_page/main_page_behavior.js
index e17f8809087f41f54231fe9eb93763c45bb28a29..532418a01d4054c21e630a04ccefc4ce8a719018 100644
--- a/chrome/browser/resources/settings/settings_page/main_page_behavior.js
+++ b/chrome/browser/resources/settings/settings_page/main_page_behavior.js
@@ -30,12 +30,6 @@ function doWhenReady(readyTest, readyCallback) {
  * @polymerBehavior Polymer.MainPageBehavior
  */
 var MainPageBehaviorImpl = {
-  /**
-   * @type {string} Selector to get the sections. Derived elements
-   *     must override.
-   */
-  sectionSelector: '',
-
   /** @type {?Element} The scrolling container. */
   scroller: null,
 
@@ -55,7 +49,7 @@ var MainPageBehaviorImpl = {
    */
   toggleOtherSectionsHidden_: function(sectionName, hidden) {
     var sections = Polymer.dom(this.root).querySelectorAll(
-        this.sectionSelector);
+        'settings-section');
     for (var section of sections)
       section.hidden = hidden && (section.section != sectionName);
   },