perform a null check in case WebContents doesn't have a ChromeDownloadDelegate

chrome/browser/android/download/download_controller.cc

Index: chrome/browser/android/download/download_controller.cc
diff --git a/chrome/browser/android/download/download_controller.cc b/chrome/browser/android/download/download_controller.cc
index 337b8ab62358f9e4b403d26def62ed649ef237f2..3768e1df89c515de902fd80251faae7edbcf349b 100644
--- a/chrome/browser/android/download/download_controller.cc
+++ b/chrome/browser/android/download/download_controller.cc
@@ -244,8 +244,12 @@ void DownloadController::OnDownloadStarted(
   // Register for updates to the DownloadItem.
   download_item->AddObserver(this);
 
-  ChromeDownloadDelegate::FromWebContents(web_contents)->OnDownloadStarted(
-      download_item->GetTargetFilePath().BaseName().value());
+  ChromeDownloadDelegate* delegate =
+      ChromeDownloadDelegate::FromWebContents(web_contents);
+  if (delegate) {
+    delegate->OnDownloadStarted(
+        download_item->GetTargetFilePath().BaseName().value());
+  }
 }
 
 void DownloadController::OnDownloadUpdated(DownloadItem* item) {