Add test_runner support for new accessibility event

content/shell/renderer/test_runner/web_test_proxy.cc

Index: content/shell/renderer/test_runner/web_test_proxy.cc
diff --git a/content/shell/renderer/test_runner/web_test_proxy.cc b/content/shell/renderer/test_runner/web_test_proxy.cc
index 37aa1f7bfaf859ddb2a809c3fcb91fe071f6d810..1ef6f85164c7b59ca327785e6fd741361a1e352c 100644
--- a/content/shell/renderer/test_runner/web_test_proxy.cc
+++ b/content/shell/renderer/test_runner/web_test_proxy.cc
@@ -755,6 +755,9 @@ void WebTestProxyBase::PostAccessibilityEvent(const blink::WebAXObject& obj,
     case blink::WebAXEventMenuListItemSelected:
       event_name = "MenuListItemSelected";
       break;
+    case blink::WebAXEventMenuListItemUnselected:
+      event_name = "MenuListItemUnselected";
+      break;
     case blink::WebAXEventMenuListValueChanged:
       event_name = "MenuListValueChanged";
       break;