When the download folder does not exist, change the download folder to a user's "Downloads"

content/browser/renderer_host/resource_dispatcher_host.cc

Index: content/browser/renderer_host/resource_dispatcher_host.cc
diff --git a/content/browser/renderer_host/resource_dispatcher_host.cc b/content/browser/renderer_host/resource_dispatcher_host.cc
index 6c195272ce7a02be798672fbcf4c504182aa18a7..3d4e3b35a519fd1dcd6c197d7b54eb9923af57dc 100644
--- a/content/browser/renderer_host/resource_dispatcher_host.cc
+++ b/content/browser/renderer_host/resource_dispatcher_host.cc
@@ -742,6 +742,7 @@ void ResourceDispatcherHost::BeginSaveFile(
     const GURL& referrer,
     int child_id,
     int route_id,
+    const FilePath& default_download_dir,
     const content::ResourceContext& context) {
   if (is_shutdown_)
     return;
@@ -750,6 +751,7 @@ void ResourceDispatcherHost::BeginSaveFile(
       new SaveFileResourceHandler(child_id,
                                   route_id,
                                   url,
+                                  default_download_dir,
                                   save_file_manager_.get()));
   request_id_--;