MD Settings: Fix Back navigation from section route to BASIC route.

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 02fbbcc869fbf63d3493b6ec7a63d8b0936c3b25..45f719b7737093136d6c972221d5d84961a1040d 100644
--- a/chrome/browser/resources/settings/settings_page/main_page_behavior.js
+++ b/chrome/browser/resources/settings/settings_page/main_page_behavior.js
@@ -30,6 +30,10 @@ var MainPageBehaviorImpl = {
     var oldRouteWasSection =
         !!oldRoute && !!oldRoute.parent && !!oldRoute.section &&
         oldRoute.parent.section != oldRoute.section;
+
+    if (oldRouteWasSection && newRoute == settings.Route.BASIC)
+      this.scroller.scrollTop = 0;

[Dan Beam, 2016/11/16 02:32:01]

do we still want to execute the code that follows this?

[tommycli, 2016/11/16 16:39:02]

Done. Indeed it does seem that the rest of the code is not necessary in this
case.

+
     var scrollToSection =
         !settings.lastRouteChangeWasPopstate() || oldRouteWasSection;