[MD settings] scroll to section find host

chrome/test/data/webui/settings/basic_page_browsertest.js

Index: chrome/test/data/webui/settings/basic_page_browsertest.js
diff --git a/chrome/test/data/webui/settings/basic_page_browsertest.js b/chrome/test/data/webui/settings/basic_page_browsertest.js
index 7410b9b02a81c053268c2f0de948c34134293d46..ae601a86f9f363b8b94a5ae231627dec73ac0f2e 100644
--- a/chrome/test/data/webui/settings/basic_page_browsertest.js
+++ b/chrome/test/data/webui/settings/basic_page_browsertest.js
@@ -51,6 +51,29 @@ TEST_F('SettingsBasicPageBrowserTest', 'MAYBE_Load', function() {
         self.verifySubpagesHidden(section);
       }
     });
+
+    // This test checks for a regression that occurred with scrollToSection_
+    // failing to find its host element.
+    test('scroll to section', function() {
+      // Setting the page and section will cause a scrollToSection_.
+      self.getPage('basic').currentRoute = {
+        page: 'basic',
+        section: 'onStartup',
+        subpage: [],
+      };
+
+      return new Promise(function(resolve, reject) {
+        function pollForVisibility() {
+          var page = self.getPage('basic')
+          var section = self.getSection(page, page.currentRoute.section);
+          if (!section)
+            setTimeout(pollForVisibility, 55);
+          else
+            resolve();
+        }
+        pollForVisibility();

[Dan Beam, 2016/05/31 22:10:29]

arguably:

var intervalId = window.setInterval(function() {
  var page = self.getPage('basic');
  var section = self.getSection(page, page.currentRoute.section);
  if (!section)
    return;

  window.clearInterval(intervalId);
  resolve();
}, 55);

or

setTimeout(function pollForVisibility() {
  var page = self.getPage('basic')
  var section = self.getSection(page, page.currentRoute.section);
  if (!section)
    setTimeout(pollForVisibility, 55);
  else
    resolve();
});

[dschuyler, 2016/05/31 22:25:02]

Done.

+      }.bind(self));
+    });
   });
 
   // Run all registered tests.