add print to pdf for headless

components/printing/renderer/print_web_view_helper.cc

 // Copyright (c) 2012 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 "components/printing/renderer/print_web_view_helper.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 877 matching lines @@
 }
 
 bool PrintWebViewHelper::Delegate::IsAskPrintSettingsEnabled() {
   return true;
 }
 
 bool PrintWebViewHelper::Delegate::IsScriptedPrintEnabled() {
   return true;
 }
 
+#if defined(OS_MACOSX)
+bool PrintWebViewHelper::Delegate::UseSingleMetafile() {
+  return false;
+}
+#endif
+
 PrintWebViewHelper::PrintWebViewHelper(content::RenderFrame* render_frame,
                                        std::unique_ptr<Delegate> delegate)
     : content::RenderFrameObserver(render_frame),
       content::RenderFrameObserverTracker<PrintWebViewHelper>(render_frame),
       reset_prep_frame_view_(false),
       is_print_ready_metafile_sent_(false),
       ignore_css_margins_(false),
       is_printing_enabled_(true),
       notify_browser_of_print_failure_(true),
       print_for_preview_(false),
@@ skipping 1460 matching lines @@
       blink::WebConsoleMessage::LevelWarning, message));
   return false;
 }
 
 void PrintWebViewHelper::ScriptingThrottler::Reset() {
   // Reset counter on successful print.
   count_ = 0;
 }
 
 }  // namespace printing