Add --headless flag to Windows

headless/test/headless_browser_test.cc

Index: headless/test/headless_browser_test.cc
diff --git a/headless/test/headless_browser_test.cc b/headless/test/headless_browser_test.cc
index 39c40d77ce6b580c2eb50028cb77fa0f0374d11b..1ad15d8077653c8302b77df83b336575ae76fb8b 100644
--- a/headless/test/headless_browser_test.cc
+++ b/headless/test/headless_browser_test.cc
@@ -211,9 +211,9 @@ void HeadlessAsyncDevTooledBrowserTest::RenderProcessExited(
   if (status == base::TERMINATION_STATUS_NORMAL_TERMINATION)
     return;
 
-  FAIL() << "Abnormal renderer termination";
   FinishAsynchronousTest();
   render_process_exited_ = true;
+  FAIL() << "Abnormal renderer termination";
 }
 
 void HeadlessAsyncDevTooledBrowserTest::RunTest() {