Google native files are no more opened in web browser

gvfsd-google uses G_FILE_TYPE_SHORTCUT for native files with G_FILE_ATTRIBUTE_STANDARD_TARGET_URI set to the official location on the web. It is a bit tricky, however, it used to work nicely. The web browser used to be opened after click on the native file. Currently, you get Could not display ...; There is no application installed for "application/vnd.google-apps..." files. error from nautilus-3.28.1-1.fc28.x86_64. No such desktop application obviously exists for the Google proprietary formats. But it doesn't work even if I modify the google backend sources to change the content type to text/html. Consequently, the web browser is opened, but not the target URI as it used to be before, but file:///run/user/.../gvfs/google-drive:host=...,user=.../..., which doesn't work...

Any idea what should be done to make this work again?

It corresponds with #448 a bit.