install HideDownloadBar from github
1. download
'Clone or download' > 'Download ZIP'
and unzip the downloaded file
2. open below in chrome
chrome://extensions/
3. check "Develop mode" in upper right of the page.
4. click 'Load unpacked extension...'
and open unzipped folder
that's all
You can change shortcut key on the below page
chrome://extensions/configureCommands