MD Settings: Scroll to top when navigating to About page.

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 6a02acd2c1b1bec4034f905809b4b105720fb183..b5093385ca99ef583ce066d0db89e0adf0da4875 100644
--- a/chrome/browser/resources/settings/settings_page/main_page_behavior.js
+++ b/chrome/browser/resources/settings/settings_page/main_page_behavior.js
@@ -48,6 +48,12 @@ var MainPageBehaviorImpl = {
       return;
     }
 
+    // Always scroll to the top when navigating to the About page.

[dschuyler, 2017/01/17 23:33:38]

I'm not sure about this, but WDYT about combining with the condition above?

// Always scroll to the top if navigating from a section to the root route
// or when navigating to the About page.
if ((oldRouteWasSection && newRoute == settings.Route.BASIC) ||
    (newRoute == settings.Route.ABOUT && this.scroller)) {
  ...
}

My concern is that if something about the body of the code needs to change in
the future, the person making that change may miss that both blocks do the same
thing and only change one of them.
If you feel that it's better as two separate condition blocks, please let me
know. 

[tommycli, 2017/01/17 23:47:00]

Done.

+    if (newRoute == settings.Route.ABOUT && this.scroller) {
+      this.scroller.scrollTop = 0;
+      return;
+    }
+
     // Scroll to the section except for back/forward. Also scroll for any
     // in-page back/forward navigations (from a section or the root page).
     var scrollToSection =