Add a mechanism to ignore certain elements for accessibility audit on a per-test basis.

chrome/test/data/webui/test_api.js

Index: chrome/test/data/webui/test_api.js
diff --git a/chrome/test/data/webui/test_api.js b/chrome/test/data/webui/test_api.js
index 04e7d4df84511d6a30979238387e7b35bd9baa5b..724b7634ada21905b525d3eeec61845889a131c9 100644
--- a/chrome/test/data/webui/test_api.js
+++ b/chrome/test/data/webui/test_api.js
@@ -888,7 +888,7 @@ var testing = {};
    * @private
    */
   function runAccessibilityAudit(a11yErrors, a11yWarnings) {
-    var auditResults = axs.Audit.run();
+    var auditResults = axs.Audit.run(this.auditConfig);
     for (var i = 0; i < auditResults.length; i++) {
       var auditResult = auditResults[i];
       if (auditResult.result == axs.constants.AuditResult.FAIL) {
@@ -975,11 +975,13 @@ var testing = {};
 
   /**
    * Asserts that the current page state passes the accessibility audit.
+   * @param {Array=} opt_errors Array to fill with errors, if desired.
+   * @param {Array=} opt_warnings Array to fill with warnings, if desired.
    */
-  function assertAccessibilityOk() {
+  function assertAccessibilityOk(opt_errors, opt_warnings) {
     helper.registerCall();
-    var a11yErrors = [];
-    var a11yWarnings = [];
+    var a11yErrors = opt_errors || [];
+    var a11yWarnings = opt_warnings || [];
     if (!runAccessibilityAudit(a11yErrors, a11yWarnings))
       throw new Error(accessibilityAuditReport(a11yErrors, a11yWarnings));
   }