add customized printing setting for headless

headless/lib/browser/headless_devtools_manager_delegate.h

Index: headless/lib/browser/headless_devtools_manager_delegate.h
diff --git a/headless/lib/browser/headless_devtools_manager_delegate.h b/headless/lib/browser/headless_devtools_manager_delegate.h
index 300cd2460080b721313de89470b085a6076d15cd..a2caf8f1cdc9e22ae7b5f99095f112aff414478c 100644
--- a/headless/lib/browser/headless_devtools_manager_delegate.h
+++ b/headless/lib/browser/headless_devtools_manager_delegate.h
@@ -13,10 +13,22 @@
 #include "base/memory/weak_ptr.h"
 #include "base/values.h"
 #include "content/public/browser/devtools_manager_delegate.h"
+#include "printing/features/features.h"
+
+#if BUILDFLAG(ENABLE_BASIC_PRINTING)
+#include "headless/lib/browser/headless_print_manager.h"
+#endif
 
 namespace headless {
 class HeadlessBrowserImpl;
 
+#if BUILDFLAG(ENABLE_BASIC_PRINTING)
+std::unique_ptr<base::DictionaryValue> ParsePrintSettings(
+    int command_id,
+    const base::DictionaryValue* params,
+    printing::HeadlessPrintSettings* settings);
+#endif
+
 class HeadlessDevToolsManagerDelegate
     : public content::DevToolsManagerDelegate {
  public: