add print to pdf for headless

headless/lib/renderer/headless_print_web_view_helper_delegate.h

+// 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.
+
+#ifndef HEADLESS_LIB_RENDERER_HEADLESS_PRINT_WEB_VIEW_HELPER_DELEGATE_H_
+#define HEADLESS_LIB_RENDERER_HEADLESS_PRINT_WEB_VIEW_HELPER_DELEGATE_H_
+
+#include "components/printing/renderer/print_web_view_helper.h"
+
+namespace headless {
+
+class HeadlessPrintWebViewHelperDelegate
+    : public printing::PrintWebViewHelper::Delegate {
+ public:
+  HeadlessPrintWebViewHelperDelegate();
+  ~HeadlessPrintWebViewHelperDelegate() override;
+
+  // PrintWebViewHelper Delegate implementation.
+  bool CancelPrerender(content::RenderFrame* render_frame) override;
+  bool IsPrintPreviewEnabled() override;
+  bool OverridePrint(blink::WebLocalFrame* frame) override;
+  bool IsAskPrintSettingsEnabled() override;
+  blink::WebElement GetPdfElement(blink::WebLocalFrame* frame) override;
+
+#if defined(OS_MACOSX)
+  bool UseSingleMetafile() override;
+#endif
+};
+
+}  // namespace headless
+
+#endif  // HEADLESS_LIB_RENDERER_HEADLESS_PRINT_WEB_VIEW_HELPER_DELEGATE_H_