Apparently valid URL is "not handleable by the URL Dispatcher"

[David Barth]

Another bug in a webapp which reveals a url dispatcher issue.

1. Start the Google Map webapp (add from the store, launch)
2. Try to sign in (top-right menu, 'Sign in')

What should happen: the sign in pocess should be redirected to the browser (it's another bug, but that's not the point of this bug report)
What happens: nothing.

In the logs, I see:

qml: Opening: https://www.google.com/accounts/ServiceLogin?service=local&hl=en&nui=1&continue=http://maps.google.com/%3Fnum%3D10 in the browser window.

** (process:21897): WARNING **: Unable to dispatch url 'https://www.google.com/accounts/ServiceLogin?service=local&hl=en&nui=1&continue=http://maps.google.com/%3Fnum%3D10':GDBus.Error:com.canonical.URLDispatcher.BadURL: URL 'https://www.google.com/accounts/ServiceLogin?service=local&hl=en&nui=1&continue=http://maps.google.com/%3Fnum%3D10' is not handleable by the URL Dispatcher

Note: This may be a re-occurence of https://bugs.launchpad.net/url-dispatcher/+bug/1324848