I have updated to Ubuntu 19.10 from CLI and, after the update, I have found a new icon on the dock.
As you can see from the picture, it is an icon to mount and open the 'GDrive' cloud service. Anyway, the icon does nothing and it seems irremovable. Also, a right-click on the icon shows an 'Add to Favorites' option and it makes no sense because the icon is already stable on the dock.
How could I remove that icon from the dock?
Please, try this command:
In Ubuntu Configuration -> online accounts, check your Google account and unmark "Files".
This action will remove that horrible icon from your dock.
I don't know if it is the right behavior, but the solution to remove internal mounted drive icons from the dock from here (How do I hide internal drive from Ubuntu Dock?) works.
If someone has a better solution, perhaps it removes the icon of the remote unit but still allows to show the internal units, it should write it here.
You can also remove your google account from the online accounts in gnome settings. This will prevent creation of the icon in the dock.
But if you use any other Google stuff (like gmail, chrome, calendar etc.), you will not be automatically logged in when you want to use that.