Use the user's preferred downloads directory for creating the initial download file.

content/browser/download/download_manager_impl.cc

Index: content/browser/download/download_manager_impl.cc
diff --git a/content/browser/download/download_manager_impl.cc b/content/browser/download/download_manager_impl.cc
index 315d6439e2f7da52743977e550c6213437a49228..293f0c7ac61ce5c6a23a4e6a3edb522c893170d5 100644
--- a/content/browser/download/download_manager_impl.cc
+++ b/content/browser/download/download_manager_impl.cc
@@ -373,6 +373,13 @@ content::DownloadId DownloadManagerImpl::StartDownload(
   // assigned in CreateDownloadItem.
   DownloadId download_id = info->download_id;
 
+  if (delegate_) {
+    FilePath website_save_directory;      // Unused
+    bool skip_dir_check = false;          // Unused
+    delegate_->GetSaveDir(GetBrowserContext(), &website_save_directory,
+                          &info->default_download_directory, &skip_dir_check);
+  }
+
   DownloadFileManager::CreateDownloadFileCallback callback(
       base::Bind(&DownloadManagerImpl::OnDownloadFileCreated,
                  this, download_id.local()));