[ios] Removed keyCode from FormActivityRegistered API.

ios/web/web_state/web_state_impl.mm

Index: ios/web/web_state/web_state_impl.mm
diff --git a/ios/web/web_state/web_state_impl.mm b/ios/web/web_state/web_state_impl.mm
index 42a8925703d86ff654cf10af090b2220e8d4c550..46897fac77b22d538386635741101230763223c3 100644
--- a/ios/web/web_state/web_state_impl.mm
+++ b/ios/web/web_state/web_state_impl.mm
@@ -239,11 +239,10 @@ void WebStateImpl::OnFormActivityRegistered(const std::string& form_name,
                                             const std::string& field_name,
                                             const std::string& type,
                                             const std::string& value,
-                                            int key_code,
                                             bool input_missing) {
   for (auto& observer : observers_) {
     observer.FormActivityRegistered(form_name, field_name, type, value,
-                                    key_code, input_missing);
+                                    input_missing);
   }
 }