MD Settings: refactor some main page properties, fix Advanced toggle

chrome/browser/resources/settings/settings_main/settings_main.js

Index: chrome/browser/resources/settings/settings_main/settings_main.js
diff --git a/chrome/browser/resources/settings/settings_main/settings_main.js b/chrome/browser/resources/settings/settings_main/settings_main.js
index 75daea44da83eb7a5e91e6f11fb9a2c469abc85b..89feb7da7b425f5f23e71cd6f8cdebd490204500 100644
--- a/chrome/browser/resources/settings/settings_main/settings_main.js
+++ b/chrome/browser/resources/settings/settings_main/settings_main.js
@@ -10,12 +10,6 @@ Polymer({
   is: 'settings-main',
 
   properties: {
-    /** @private */
-    isAdvancedMenuOpen_: {
-      type: Boolean,
-      value: false,
-    },
-
     /**
      * Preferences state.
      */
@@ -35,27 +29,34 @@ Polymer({
     },
 
     /** @private */
-    showAdvancedPage_: {
+    advancedToggleExpanded_: {
       type: Boolean,
       value: false,
     },
 
     /** @private */
-    showAdvancedToggle_: {
+    inSubpage_: {
+      type: Boolean,
+      computed: 'computeInSubpage_(currentRoute.subpage)',
+    },
+
+    /** @private */
+    showAboutPage_: {
       type: Boolean,
-      value: true,
+      computed: 'computeShowAboutPage_(currentRoute.page)',
     },
 
     /** @private */
     showBasicPage_: {
       type: Boolean,
-      value: true,
+      computed: 'computeShowBasicPage_(currentRoute.page, inSubpage_)',
     },
 
     /** @private */
-    showAboutPage_: {
+    showAdvancedPage_: {
       type: Boolean,
-      value: false,
+      computed: 'computeShowAdvancedPage_(' +
+          'currentRoute.page, advancedToggleExpanded_, inSubpage_)',
     },
   },
 
@@ -68,14 +69,13 @@ Polymer({
 
   attached: function() {
     document.addEventListener('toggle-advanced-page', function(e) {
-      this.showAdvancedPage_ = e.detail;
-      this.isAdvancedMenuOpen_ = e.detail;
+      this.advancedToggleExpanded_ = e.detail;
       this.currentRoute = {
-        page: this.isAdvancedMenuOpen_ ? 'advanced' : 'basic',
+        page: this.advancedToggleExpanded_ ? 'advanced' : 'basic',
         section: '',
         subpage: [],
       };
-      if (this.showAdvancedPage_) {
+      if (this.advancedToggleExpanded_) {
         doWhenReady(
             function() {
               var advancedPage = this.$$('settings-advanced-page');
@@ -101,7 +101,7 @@ Polymer({
    * @param {boolean} opened Whether the menu is expanded.
    * @return {string} Which icon to use.
    * @private
-   * */
+   */
   arrowState_: function(opened) {
     return opened ? 'settings:arrow-drop-up' : 'cr:arrow-drop-down';
   },
@@ -111,24 +111,16 @@ Polymer({
    * @private
    */
   currentRouteChanged_: function(newRoute) {
-    var isSubpage = !!newRoute.subpage.length;
+    // If we navigated to an advanced section, ensure the toggle is opened.
+    if (newRoute.page == 'advanced')
+      this.advancedToggleExpanded_ = true;
 
-    this.showAboutPage_ = newRoute.page == 'about';
-
-    this.showAdvancedToggle_ = !this.showAboutPage_ && !isSubpage;
-
-    this.showBasicPage_ = this.showAdvancedToggle_ || newRoute.page == 'basic';
-
-    this.showAdvancedPage_ =
-        (this.isAdvancedMenuOpen_ && this.showAdvancedToggle_) ||
-        newRoute.page == 'advanced';
-
-    this.style.height = isSubpage ? '100%' : '';
+    this.style.height = this.inSubpage_ ? '100%' : '';
   },
 
   /** @private */
   toggleAdvancedPage_: function() {
-    this.fire('toggle-advanced-page', !this.isAdvancedMenuOpen_);
+    this.fire('toggle-advanced-page', !this.advancedToggleExpanded_);
   },
 
   /**
@@ -162,4 +154,45 @@ Polymer({
       settings.search(query, assert(this.$$('settings-advanced-page')));
     }.bind(this), 0);
   },
+
+  /**
+   * @return {boolean}
+   * @param {!Array<string>} subpage
+   * @private
+   */
+  computeInSubpage_: function(subpage) {
+    return !!subpage.length;
+  },
+
+  /**
+   * @param {string} page
+   * @return {boolean}
+   * @private
+   */
+  computeShowAboutPage_: function(page) {
+    return page == 'about';
+  },
+
+  /**
+   * @param {string} page
+   * @param {boolean} inSubpage
+   * @return {boolean}
+   * @private
+   */
+  computeShowBasicPage_: function(page, inSubpage) {
+    return page == 'basic' ||
+           (page == 'advanced' && !inSubpage);
+  },
+
+  /**
+   * @param {string} page
+   * @param {boolean} advancedToggleExpanded
+   * @param {boolean} inSubpage
+   * @return {boolean}
+   * @private
+   */
+  computeShowAdvancedPage_: function(page, advancedToggleExpanded, inSubpage) {
+    return page == 'advanced' ||
+           (page == 'basic' && advancedToggleExpanded && !inSubpage);
+  },
 });