check whether the printing render frame host has been initialised before accepting a message in the…

headless/lib/headless_browser_browsertest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <memory>
 
 #include "base/command_line.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_util.h"
 #include "base/memory/ptr_util.h"
@@ skipping 877 matching lines @@
   EXPECT_NE(nullptr, target);
 
   TraceHelper helper(this, target);
   RunAsynchronousTest();
 
   std::unique_ptr<base::ListValue> tracing_data = helper.TakeTracingData();
   EXPECT_TRUE(tracing_data);
   EXPECT_LT(0u, tracing_data->GetSize());
 }
 
+IN_PROC_BROWSER_TEST_F(HeadlessBrowserTest, WindowPrint) {
+  EXPECT_TRUE(embedded_test_server()->Start());
+
+  HeadlessBrowserContext* browser_context =
+      browser()->CreateBrowserContextBuilder().Build();
+
+  HeadlessWebContents* web_contents =
+      browser_context->CreateWebContentsBuilder()
+          .SetInitialURL(embedded_test_server()->GetURL("/hello.html"))
+          .Build();
+  EXPECT_TRUE(WaitForLoad(web_contents));
+  EXPECT_FALSE(
+      EvaluateScript(web_contents, "window.print()")->HasExceptionDetails());
+}
+
 }  // namespace headless