MD History: Disable individual failing List test rather than entire suite

chrome/test/data/webui/md_history/history_list_test.js

 // Copyright 2016 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.
 
 suite('<history-list>', function() {
   var app;
   var element;
   var toolbar;
   var TEST_HISTORY_RESULTS;
   var ADDITIONAL_RESULTS;
@@ skipping 479 matching lines @@
 
       registerMessageCallback('navigateToUrl', this, function(info) {
         assertEquals(fileURL, info[0]);
         done();
       });
 
       MockInteractions.tap(items[0].$.title);
     });
   });
 
-  test('focus and keyboard nav', function(done) {
+  // Test is very flaky on all platforms, http://crbug.com/669227.
+  test.skip('focus and keyboard nav', function(done) {
     app.historyResult(createHistoryInfo(), TEST_HISTORY_RESULTS);
     PolymerTest.flushTasks().then(function() {
       var items = polymerSelectAll(element, 'history-item');
 
       var focused = items[2].$.checkbox;
       focused.focus();
 
       // Wait for next render to ensure that focus handlers have been
       // registered (see HistoryItemElement.attached).
       Polymer.RenderStatus.afterNextRender(this, function() {
@@ skipping 40 matching lines @@
     });
   });
 
   teardown(function() {
     registerMessageCallback('removeVisits', this, undefined);
     registerMessageCallback('queryHistory', this, function() {});
     registerMessageCallback('navigateToUrl', this, undefined);
     app.set('queryState_.searchTerm', '');
   });
 });