Move settings-section animations into setting-section, make better

chrome/browser/resources/settings/settings_main/settings_main.html

 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/html/promise_resolver.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="/about_page/about_page.html">
 <link rel="import" href="/advanced_page/advanced_page.html">
 <link rel="import" href="/basic_page/basic_page.html">
 <link rel="import" href="/settings_main/settings_main_rendered.html">
 <link rel="import" href="/settings_page/main_page_behavior.html">
 <link rel="import" href="/settings_root_css.html">
@@ skipping 20 matching lines @@
 
       #toggleSpacer {
         padding-top: 33px;  /* Part of a 48px spacer (33px + 12px + 3px). */
       }
 
       iron-icon {
         -webkit-margin-start: 16px;
       }
     </style>
     <content select="paper-icon-button"></content>
-    <template is="dom-if" if="[[showBasicPage_]]">
-      <settings-basic-page prefs="{{prefs}}" current-route="{{currentRoute}}">
-      </settings-basic-page>
-    </template>
-    <template is="dom-if" if="[[showAdvancedToggle_]]">
-      <div id="toggleSpacer"></div>
-      <div id="toggleContainer">
-        <div id="advancedToggle" on-tap="toggleAdvancedPage_">
-          <span>$i18n{advancedPageTitle}</span>
-          <iron-icon icon="[[arrowState_(showAdvancedPage_)]]"></iron-icon>
+    <template is="dom-if" if="[[!showAboutPage_]]">
+      <template is="dom-if" if="[[showBasicPage_]]">
+        <settings-basic-page prefs="{{prefs}}" current-route="{{currentRoute}}"
+            on-subpage-expand="subpageExpanded_"
+            on-subpage-collapsing="subpageCollapsing_">
+        </settings-basic-page>
+      </template>
+      <div hidden$="[[inSubpage_]]">
+        <div id="toggleSpacer"></div>
+        <div id="toggleContainer">
+          <div id="advancedToggle" on-tap="toggleAdvancedPage_">
+            <span>$i18n{advancedPageTitle}</span>
+            <iron-icon icon="[[arrowState_(showAdvancedPage_)]]">
+            </iron-icon>
+          </div>
         </div>
       </div>
-    </template>
-    <template is="dom-if" if="[[showAdvancedPage_]]">
-      <settings-advanced-page prefs="{{prefs}}"
-          current-route="{{currentRoute}}">
-      </settings-advanced-page>
+      <template is="dom-if" if="[[showAdvancedPage_]]">
+        <settings-advanced-page prefs="{{prefs}}"
+            current-route="{{currentRoute}}"
+            on-subpage-expand="subpageExpanded_"
+            on-subpage-collapsing="subpageCollapsing_">
+        </settings-advanced-page>
+      </template>
     </template>
     <template is="dom-if" if="[[showAboutPage_]]">
       <settings-about-page current-route="{{currentRoute}}">
       </settings-about-page>
     </template>
   </template>
   <script src="settings_main.js"></script>
 </dom-module>