MD Settings: Scroll correctly for navigations that exit search mode.

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /** @fileoverview Suite of tests for the Settings basic page. */
 
 GEN_INCLUDE(['settings_page_browsertest.js']);
 
 /**
  * @constructor
@@ skipping 63 matching lines @@
 
         return new Promise(function(resolve) {
           listenOnce(window, 'popstate', resolve);
           settings.navigateToPreviousRoute();
         });
       }).then(function() {
         // Should be at the top of the page after going Back from the section.
         assertEquals(0, page.scroller.scrollTop);
       });
     });
+
+    test('scroll to section after exiting search', function() {
+      // Enter search mode to show all the sections.
+      var settingsMain = Polymer.dom().querySelector('* /deep/ settings-main');
+      assert(!!settingsMain);
+      settingsMain.inSearchMode_ = true;
+      Polymer.dom.flush();
+
+      // Set all the sections to be hidden by search.
+      var sections =
+          Polymer.dom().querySelectorAll('* /deep/ settings-section');
+      for (var i = 0; i < sections.length; i++)
+        sections[i].hiddenBySearch = true;

[dpapad, 2016/12/07 00:57:10]

Lines 87 to 96, redo what the actual code does, seems a bit fragile and accesses
private member vars. Can we invoke search properly (by calling
settings-main#searchContents() and have all that done automatically?

[tommycli, 2016/12/08 00:52:15]

Done. This was so nasty I spent all day trying cleaning this up.

+      Polymer.dom.flush();
+
+      // Verify that the On Startup section is hidden.
+      var page = self.getPage('basic');
+      var onStartup = self.getSection(page, 'onStartup');
+      assertTrue(!!onStartup);
+      assertEquals(0, onStartup.offsetHeight);
+
+      return new Promise(function(resolve) {
+        // Manually set the last search query to something different to trigger
+        // the search clearing code when we navigate.
+        var settingsUi = Polymer.dom().querySelector('* /deep/ settings-ui');
+        assert(!!settingsUi);
+        settingsUi.lastSearchQuery_ = 'foobar';
+
+        settings.navigateTo(settings.Route.ON_STARTUP,
+                            /* dynamicParams */ null,
+                            /* removeSearch */ true);
+
+        // Should (after some time) be scrolled to the On Startup section.
+        var intervalId = window.setInterval(function() {
+          if (page.scroller.scrollTop != 0) {
+            window.clearInterval(intervalId);
+            resolve();
+          }
+        }, 55);
+      });
+    });
   });
 
   // Run all registered tests.
   mocha.run();
 });