0x000000010b75cc77	(Google Chrome Framework -web_contents_user_data.h:52 )	constrained_window::ShowWebModalDialogViews(views::WidgetDelegate*, content::WebContents*)
0x000000010b598783	(Google Chrome Framework -folder_upload_confirmation_view.cc:52 )	FolderUploadConfirmationView::ShowDialog(base::FilePath const&, base::OnceCallback<void (std::__1::vector<ui::SelectedFileInfo, std::__1::allocator<ui::SelectedFileInfo> > const&)>, std::__1::vector<ui::SelectedFileInfo, std::__1::allocator<ui::SelectedFileInfo> >, content::WebContents*)
0x000000010b598a3b	(Google Chrome Framework -folder_upload_confirmation_view.cc:103 )	ShowFolderUploadConfirmationDialog(base::FilePath const&, base::OnceCallback<void (std::__1::vector<ui::SelectedFileInfo, std::__1::allocator<ui::SelectedFileInfo> > const&)>, std::__1::vector<ui::SelectedFileInfo, std::__1::allocator<ui::SelectedFileInfo> >, content::WebContents*)
0x000000010883dc0d	(Google Chrome Framework -file_select_helper.cc:250 )	FileSelectHelper::LaunchConfirmationDialog(base::FilePath const&, std::__1::vector<ui::SelectedFileInfo, std::__1::allocator<ui::SelectedFileInfo> >)
0x000000010883e059	(Google Chrome Framework -file_select_helper.cc:269 )	FileSelectHelper::OnListDone(int)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/088a341f7d0a9110b2cca2f8803b7bbe006f0dc4

commit 088a341f7d0a9110b2cca2f8803b7bbe006f0dc4
Author: Collin Baker <collinbaker@chromium.org>
Date: Fri Jan 04 23:27:19 2019

Fix crash when tab is closed during folder upload

FileSelectHelper::OnListDone(), which is called when directory listing
is complete, launches an upload confirmation dialog associated with
the WebContents the upload request originated from. It does not
consider the case where the WebContents has been destroyed.

FileSelectHelper already handles the WebContentsDestroyed message, and
sets its web_contents_ member to null accordingly. All that needs to
be done is cleanup and an early return in OnListDone() if web_contents_
is null.

Bug:  916529 
Change-Id: Ic362c42a72a2c83bf21ad798d4b05c080c4b972f
Reviewed-on: https://chromium-review.googlesource.com/c/1395138
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Collin Baker <collinbaker@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620104}
[modify] https://crrev.com/088a341f7d0a9110b2cca2f8803b7bbe006f0dc4/chrome/browser/file_select_helper.cc

Tried reproducing the issue on chrome reported version# 73.0.3642.0 using Windows-10 with steps mentioned below:
1) Launched chrome reported version and navigated to URL: https://ludios.org/tmp/upload_folder.html
2) Clicked on 'Choose File' and selected the folder which has 1300 files in it and clicked on 'Upload'
3) Immediately after clicking on 'Upload' option, seen "Upload 1300 files to this site?" pop-up on the screen

Collin Baker/ivan@ludios.org@ Please find above mentioned information and attached screencast for your reference. Could you please try to test this issue on latest chrome# 73.0.3664.0 and help us in verifying the fix.

Thanks!

Deleted: 916529.mp4 855 KB

	916529.mp4 855 KB View Download

This is easier to test by selecting a folder with a large nested directory tree with e.g. 100K files, because the child folders won't all be in the OS cache.

I verified this is fixed in Version 73.0.3664.0 (Official Build) canary (64-bit) on Windows 10.

I forgot to mark this fixed on Friday.

But yeah, that folder wasn't large enough to reproduce the issue. It has to be large enough for the confirmation pop-up to not immediately show.