Fix a failure in test_api.js when accessibility auditing is not enabled.

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 abd27ae3826b49aeef251ea653209b42d13ba840..be8664310a231be58f9744c91e67ac0f509155e3 100644
--- a/chrome/test/data/webui/test_api.js
+++ b/chrome/test/data/webui/test_api.js
@@ -150,7 +150,12 @@ var testing = {};
      * @return {axs.AuditConfiguration}
      */
     get accessibilityAuditConfig() {
-      if (!this.accessibilityAuditConfig_) {
+      // The axs namespace is not available in chromevox tests.
+      // Further, 'window' is not available in unit tests, but since the
+      // accessibility audit library pulls in the closure library,
+      // 'goog.global' has to be present if axs is, so we use that here.
+      if (!this.accessibilityAuditConfig_ &&
+          goog && goog.global && goog.global.axs) {
         this.accessibilityAuditConfig_ = new axs.AuditConfiguration();
 
         this.accessibilityAuditConfig_.showUnsupportedRulesWarning = false;
@@ -281,14 +286,17 @@ var testing = {};
      * @type {Function}
      */
     setUp: function() {
-      // These should be ignored in many of the web UI tests.
-      // user-image-stream and supervised-user-creation-image-stream are
-      // streaming video elements used for capturing a user image so they won't
-      // have captions and should be ignored everywhere.
-      this.accessibilityAuditConfig.ignoreSelectors('videoWithoutCaptions',
-                                                    '.user-image-stream');
-      this.accessibilityAuditConfig.ignoreSelectors(
-          'videoWithoutCaptions', '.supervised-user-creation-image-stream');
+      var auditConfig = this.accessibilityAuditConfig;
+      if (auditConfig) {
+        // These should be ignored in many of the web UI tests.
+        // user-image-stream and supervised-user-creation-image-stream are
+        // streaming video elements used for capturing a user image so they
+        // won't have captions and should be ignored everywhere.
+        auditConfig.ignoreSelectors('videoWithoutCaptions',
+                                    '.user-image-stream');
+        auditConfig.ignoreSelectors(
+            'videoWithoutCaptions', '.supervised-user-creation-image-stream');
+      }
     },
 
     /**