add print to pdf for headless

headless/lib/renderer/headless_content_renderer_client.cc

Index: headless/lib/renderer/headless_content_renderer_client.cc
diff --git a/headless/lib/renderer/headless_content_renderer_client.cc b/headless/lib/renderer/headless_content_renderer_client.cc
new file mode 100644
index 0000000000000000000000000000000000000000..52e40774b049f6d362363e26e8ba26ff20e83a82
--- /dev/null
+++ b/headless/lib/renderer/headless_content_renderer_client.cc
@@ -0,0 +1,23 @@
+// Copyright 2017 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 "headless/lib/renderer/headless_content_renderer_client.h"
+
+#include "base/memory/ptr_util.h"
+#include "components/printing/renderer/print_web_view_helper.h"
+#include "headless/lib/renderer/headless_print_web_view_helper_delegate.h"
+
+namespace headless {
+
+HeadlessContentRendererClient::HeadlessContentRendererClient() {}
+
+HeadlessContentRendererClient::~HeadlessContentRendererClient() {}
+
+void HeadlessContentRendererClient::RenderFrameCreated(
+    content::RenderFrame* render_frame) {
+  new printing::PrintWebViewHelper(
+      render_frame, base::MakeUnique<HeadlessPrintWebViewHelperDelegate>());
+}
+
+}  // namespace headless