Fix double Google Chrome icon in Elementary OS Plank

After recent Google Chrome update I've got it's icon doubled in Plank (one copy is "locked" in dock, "another copy" appears when you launch Chrome).

To fix it you need to modify desktop launcher file
sudo gedit /usr/share/applications/google-chrome.desktop

Inside you can see 3 sections like "[Desktop Entry]", under each add a following line
StartupWMClass=Google-chrome-stable

Then close Chrome, remove icon fron Plank and restart Chrome. Then re-lock icon.

Troubleshooting

If you will get Your profile could not be opened correctly error on browser launch - try to kill all Chrome processes (some background one could lock your profile data) by
sudo killall -9 chrome