From dee324f79a9bfc27cf1d92325597cea5c2b9d199 Mon Sep 17 00:00:00 2001
From: Cheng Zhao <zcbenz@gmail.com>
Date: Thu, 6 Feb 2020 00:48:51 +0900
Subject: [PATCH] fix: check WebContents in OnGetDefaultPrinter (#22041)

---
 shell/browser/api/electron_api_web_contents.cc | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/shell/browser/api/electron_api_web_contents.cc b/shell/browser/api/electron_api_web_contents.cc
index af19cdfd588..eb06d1c43bd 100644
--- a/shell/browser/api/electron_api_web_contents.cc
+++ b/shell/browser/api/electron_api_web_contents.cc
@@ -1745,6 +1745,14 @@ void WebContents::OnGetDefaultPrinter(
     base::string16 device_name,
     bool silent,
     base::string16 default_printer) {
+  // The content::WebContents might be already deleted at this point, and the
+  // PrintViewManagerBasic class does not do null check.
+  if (!web_contents()) {
+    if (print_callback)
+      std::move(print_callback).Run(false, "failed");
+    return;
+  }
+
   base::string16 printer_name =
       device_name.empty() ? default_printer : device_name;
   print_settings.SetStringKey(printing::kSettingDeviceName, printer_name);