diff --git a/tests/shared/browser/client_app_browser.cc b/tests/shared/browser/client_app_browser.cc
index e02ef7b93..adf2fffbd 100644
--- a/tests/shared/browser/client_app_browser.cc
+++ b/tests/shared/browser/client_app_browser.cc
@@ -47,6 +47,11 @@ void ClientAppBrowser::OnBeforeCommandLineProcessing(
       command_line->AppendSwitch("disable-gpu-shader-disk-cache");
     }
 
+#if defined(OS_MACOSX)
+    // Disable the toolchain prompt on macOS.
+    command_line->AppendSwitch("use-mock-keychain");
+#endif
+
     DelegateSet::iterator it = delegates_.begin();
     for (; it != delegates_.end(); ++it)
       (*it)->OnBeforeCommandLineProcessing(this, command_line);