No, there’s no such plugin (yet) as this would require some kind of servers handling this. One workaround might be to store bookmarks in a cloud folder (e.g. Dropbox) and to index this folder on the Mac. And DEVONthink 3 could then convert these bookmarks to the desired format via smart rules or AppleScript.
When I must clip from windows (for example), I clip con external tools (PrintPDF for example). Once I have the PDF, I go to iCloud.com and I have a synchronized folder in iCloudDrive with a “Fast Action” (sorry, my Macs are in Spanish and I don’t know the English name) that is to move the files put there into DT.
When one of my Macs wakes up for any reason, the combination of DT and file system automatically moves the file into DT. Some times this happens in ten minutes, sometimes it happens after some hours.