Add an accessibility audit test for WebUI pages

chrome/test/data/webui/history_browsertest.js

Index: chrome/test/data/webui/history_browsertest.js
diff --git a/chrome/test/data/webui/history_browsertest.js b/chrome/test/data/webui/history_browsertest.js
index dc8afaf5520208131fcd557a44f3ae0f37980eba..e5e6de9b49ca190d764b68d00becf6e41b757cca 100644
--- a/chrome/test/data/webui/history_browsertest.js
+++ b/chrome/test/data/webui/history_browsertest.js
@@ -38,6 +38,9 @@ BaseHistoryWebUITest.prototype = {
 
   isAsync: true,
 
+  runA11yChecks: false,
+  a11yIssuesAreErrors: false,
+
   /**
    * Register handlers to stub out calls to the history backend.
    * @override
@@ -107,12 +110,15 @@ TEST_F('BaseHistoryWebUITest', 'emptyHistory', function() {
 });
 
 TEST_F('HistoryWebUITest', 'basicTest', function() {
+  enableA11yChecks();
+
   var resultCount = document.querySelectorAll('.entry').length;
 
   // Check that there are two days of entries.
   var dayHeaders = document.querySelectorAll('.day');
   assertEquals(2, dayHeaders.length);
   expectNotEquals(dayHeaders[0].textContent, dayHeaders[1].textContent);
+  expectAccessibilityOk();
 
   // Check that the entries in each day are time-ordered, and that no
   // duplicate URLs appear on a given day.