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

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 f80a8512c0c54b21bc89b73ddfbf8271534494f2..2c5dcacb5615222af84a1e7072eb73a3ee98c69f 100644
--- a/chrome/browser/resources/settings/settings_main/settings_main.js
+++ b/chrome/browser/resources/settings/settings_main/settings_main.js
@@ -34,7 +34,12 @@ Polymer({
       value: false,
     },
 
-    /** @private */
+    /**
+     * True if a section is expanded to show a subpage. Initialized using
+     * currentRoute. Toggles based on expand/collapse events so effects can
+     * be deferred until transitions complete.
+     * @private
+     */
     inSubpage_: Boolean,
 
     /**
@@ -89,6 +94,8 @@ Polymer({
         function() {
           this.resolver_.resolve();
         }.bind(this));
+
+    this.inSubpage_ = this.currentRoute.subpage.length > 0;

[Dan Beam, 2016/07/23 01:13:44]

so we don't need to call updatePagesShown_() here? because we're doing it from
currentRouteChanged_?

   },
 
   /**
@@ -114,16 +121,36 @@ Polymer({
    * @private
    */
   currentRouteChanged_: function(newRoute) {
-    this.inSubpage_ = newRoute.subpage.length > 0;
-    this.style.height = this.inSubpage_ ? '100%' : '';
+    this.updatePagesShown_();
+  },
 
-    if (newRoute.page == 'about') {
-      this.showPages_ = {about: true, basic: false, advanced: false};
+  /** @private */
+  subpageExpanded_: function() {
+    this.inSubpage_ = true;
+    // Hide pages other than the current section's parent page.
+    this.updatePagesShown_();
+  },
+
+  /** @private */
+  subpageCollapsing_: function() {
+    this.inSubpage_ = false;
+    // Unhide pages before collapsing the full-height section.
+    this.updatePagesShown_();
+  },
+
+  /**
+   * Updates the hidden state of the about, basic and advanced pages, based on
+   * the current route and the Advanced toggle state.
+   * @private
+   */
+  updatePagesShown_: function() {
+    if (this.currentRoute.page == 'about') {
+      this.showPages_ = {about: true, advanced: false, basic: false};
     } else {
       this.showPages_ = {
         about: false,
-        basic: newRoute.page == 'basic' || !this.inSubpage_,
-        advanced: newRoute.page == 'advanced' ||
+        basic: this.currentRoute.page == 'basic' || !this.inSubpage_,
+        advanced: this.currentRoute.page == 'advanced' ||
             (!this.inSubpage_ && this.advancedToggleExpanded_),
       };