MD Settings: Remove subpage animation when landing directly on it.

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 6983546cefafa7429188c946682390539963ffc3..f2c42fc78118a6c0fc7e68ec4f4cb42a71a6a02b 100644
--- a/chrome/browser/resources/settings/settings_page/main_page_behavior.js
+++ b/chrome/browser/resources/settings/settings_page/main_page_behavior.js
@@ -35,9 +35,7 @@ var MainPageBehaviorImpl = {
   /** @type {?HTMLElement} The scrolling container. */
   scroller: null,
 
-  listeners: {
-    'neon-animation-finish': 'onNeonAnimationFinish_'
-  },
+  listeners: {'neon-animation-finish': 'onNeonAnimationFinish_'},
 
   /** @override */
   attached: function() {
@@ -90,9 +88,12 @@ var MainPageBehaviorImpl = {
 
     // For previously uncreated pages (including on first load), allow the page
     // to render before scrolling to or expanding the section.
-    if (!oldRoute || this.scrollHeight == 0)
-      setTimeout(this.tryTransitionToSection_.bind(this, scrollToSection));
-    else
+    if (!oldRoute || this.scrollHeight == 0) {
+      document.body.querySelector('settings-ui::shadow #container')

[michaelpg, 2017/04/22 04:01:58]

::shadow makes me sad, is there no other way to get to the container?

[scottchen, 2017/04/26 17:26:40]

I changed settings-ui to pass a "shouldHideContainer" flag that can be changed
by mainPageBehavior.

+          .setAttribute('hidden', true);

[scottchen, 2017/04/19 18:05:22]

without this line, the basic page will briefly appear before landing on the
subpage:
https://drive.google.com/a/google.com/file/d/0ByIc0PEad7DmN1IzQnR0TDFYQkE/vie...

[michaelpg, 2017/04/22 04:01:58]

Yeah, it's probably necessary unless we want to make bigger changes. It would be
nice if we could call toggleOtherSectionsHidden, but that doesn't work if the
other sections aren't stamped yet >_<

[scottchen, 2017/04/26 17:26:40]

Acknowledged.

+      setTimeout(
+          this.tryTransitionToSection_.bind(this, scrollToSection, true));
+    } else
       this.tryTransitionToSection_(scrollToSection);
   },
 
@@ -118,7 +119,9 @@ var MainPageBehaviorImpl = {
    * @param {boolean} scrollToSection
    * @private
    */
-  tryTransitionToSection_: function(scrollToSection) {
+  tryTransitionToSection_: function(scrollToSection, immediate) {
+    document.body.querySelector('settings-ui::shadow #container')

[michaelpg, 2017/04/22 04:01:58]

Does this only take effect on the first call? Perhaps it's better to unset this
up on line 95, in the setTimeout (the same place we add the attribute) before
calling tryTransitionToSection.

e.g., something like
  setTimeout(function() {
    document.body......removeAttribute('hidden');
    this.tryTransitionToSection_(scrollToSection, true);
  }.bind(this));

[scottchen, 2017/04/26 17:26:40]

Done.

+        .removeAttribute('hidden');
     var currentRoute = settings.getCurrentRoute();
     var currentSection = this.getSection(currentRoute.section);
 
@@ -144,7 +147,7 @@ var MainPageBehaviorImpl = {
     } else if (currentSection) {
       // Expand the section into a subpage or scroll to it on the main page.
       if (currentRoute.isSubpage())
-        promise = this.expandSection_(currentSection);
+        promise = this.expandSection_(currentSection, immediate);
       else if (scrollToSection)
         currentSection.scrollIntoView();
     } else if (
@@ -207,9 +210,20 @@ var MainPageBehaviorImpl = {
    * @return {!Promise} Resolved when the transition is finished or canceled.
    * @private
    */
-  expandSection_: function(section) {
+  expandSection_: function(section, immediate) {
     assert(this.scroller);
 
+    if (immediate) {
+      section.immediateExpand(this.scroller);
+
+      this.classList.add('showing-subpage');
+      this.toggleOtherSectionsHidden_(section.section, true);
+      this.scroller.scrollTop = 0;

[michaelpg, 2017/04/22 04:01:58]

when is this not starting at 0?

[scottchen, 2017/04/26 17:26:41]

Never, this is not necessary. Removing.

+      // Notify that the page is fully expanded.
+      this.fire('subpage-expand');
+      return;
+    }
+
     if (!section.canAnimateExpand()) {
       // Try to wait for the section to be created.

[michaelpg, 2017/04/22 04:01:58]

We *might* not need this anymore if the goal is to show sub-pages immediately on
load, so you could replace this with the body of the `if` above and not have to
add the |immediate| parameter.

(But maybe it's still necessary if we haven't stamped Advanced yet, and we
navigate to an Advanced subpage?)

[scottchen, 2017/04/26 17:26:40]

Using !section.canAnimateExpand() to indicate first-load doesn't seem explicit
enough - canAnimateExpand() can also return false if it's half way through the
expanding animation, so I think it's safer to keep them separate.

       return new Promise(function(resolve, reject) {