Version: 49.0.2623.39 beta-m (64-bit)
OS: Windows 7

What steps will reproduce the problem?
1. Open chrome://extensions/
2. Click "Developer Mode"
3. Click "Load unpacked extension"

OBSERVE: Folder picker dialog shows a meaningless "Make New Folder" button.

Windows' shbrowseforfolder button offers a flag to suppress this button

BIF_NONEWFOLDERBUTTON (0x00000200)
0x00000200. Version 6.0. Do not include the New Folder button in the browse dialog box.

https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/extensions/api/developer_private/developer_private_api.cc&sq=package:chromium&type=cs&l=725