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

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 9fde2be0af3303f876535a5e2aadf5c362832897..8e1b2d90ffd8a434b6b1933a540d1ac01f8df165 100644
--- a/chrome/test/data/webui/settings/basic_page_browsertest.js
+++ b/chrome/test/data/webui/settings/basic_page_browsertest.js
@@ -13,7 +13,12 @@ GEN_INCLUDE(['settings_page_browsertest.js']);
 function SettingsBasicPageBrowserTest() {}
 
 SettingsBasicPageBrowserTest.prototype = {
-  __proto__: SettingsPageBrowserTest.prototype
+  __proto__: SettingsPageBrowserTest.prototype,
+
+  /** @override */
+  extraLibraries: SettingsPageBrowserTest.prototype.extraLibraries.concat([
+    'test_browser_proxy.js',
+  ]),
 };
 
 // Times out on debug builders and may time out on memory bots because
@@ -30,6 +35,49 @@ TEST_F('SettingsBasicPageBrowserTest', 'MAYBE_Load', function() {
   // and test() will be a Mocha 'Suite' or 'Test' instance.
   var self = this;
 
+  /**
+   * This fake SearchManager just hides and re-displays the sections on search.
+   *
+   * @implements {SearchManager}
+   * @extends {settings.TestBrowserProxy}
+   */
+  var TestSearchManager = function() {
+    settings.TestBrowserProxy.call(this, [
+      'search',
+    ]);
+
+    /** @private {?settings.SearchRequest} */
+    this.searchRequest_ = null;
+  }
+
+  TestSearchManager.prototype = {
+    __proto__: settings.TestBrowserProxy.prototype,
+
+    /** @override */
+    search: function(text, page) {
+      if (this.searchRequest_ == null || !this.searchRequest_.isSame(text)) {
+        this.searchRequest_ = new settings.SearchRequest(text);
+        this.searchRequest_.finished = true;
+        this.searchRequest_.updateMatches(false);
+
+        // The search much be resolved asynchronously just like the real
+        // SearchManager. Otherwise, the race condition doesn't manifest.
+        setTimeout(function() {
+          // All the sections must be hidden by the TestSearchManager, just like
+          // the real SearchManager. Otherwise, the bug doesn't manifest.
+          var sections =
+              Polymer.dom().querySelectorAll('* /deep/ settings-section');
+          for (var i = 0; i < sections.length; i++)
+            sections[i].hiddenBySearch = !!text;
+
+          this.searchRequest_.resolver.resolve(this.searchRequest_);
+          this.methodCalled('search', text);
+        }.bind(this), 0);
+      }
+      return this.searchRequest_.resolver.promise;
+    },
+  };
+
   // Register mocha tests.
   suite('SettingsPage', function() {
     test('load page', function() {
@@ -81,6 +129,33 @@ TEST_F('SettingsBasicPageBrowserTest', 'MAYBE_Load', function() {
         assertEquals(0, page.scroller.scrollTop);
       });
     });
+
+    test('scroll to section after exiting search', function() {
+      var searchManager = new TestSearchManager();
+      settings.setSearchManagerForTesting(searchManager);
+
+      settings.navigateTo(settings.Route.BASIC,
+                          new URLSearchParams(`search=foobar`),
+                          /* removeSearch */ false);
+      return searchManager.whenCalled('search').then(function() {
+        return new Promise(function(resolve) {
+          settings.navigateTo(settings.Route.ON_STARTUP,
+                              /* dynamicParams */ null,
+                              /* removeSearch */ true);
+
+          var page = self.getPage('basic');
+          assertTrue(!!page);
+
+          // 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.