When hitting enter after typing something in the URLBar, we end up calling _canonizeURL(), which in turn calls getShortcutOrURIAndPostData() - this looks up keyword searches. With UnifiedComplete enabled, this should entirely be handled by UnifiedComplete. The only processing the URLBar binding should be doing is handling moz-action URIs and adding the right suffixes (the later of which would be nice to move into UnifiedComplete also).
This is more a code cleanup thing than a bug needed for unified complete. I also don't think we can do this before we stop allowing to disable unified complete, it would just make the code more complicated.
bug 1310737 has completed the inversion of behavior where now the awesomebar decides what to load, rather than the docshell (apart a single case where the docshell may try to resolve a domain and then fallback to a search). We now pass through getShortcutOrURI only in legacy testing code and add-ons, but the normal flow won't go through it, so we don't run twice the code figuring out if something is a keyword or an alias.
Removing the keyword since this bug doesn't have a patch and bug 1310737 was verified.