I don't fully agree with you there.
I assume constitutional monarchy = people elect the guys sitting in the parliament, but the king decides who forms the government and has to sign all laws, before they are enacted.
Democracy = same as before, except the king has absolutely nothing to say.
Now I can't say for all other countries, but afaik quite a lot of the countries that we consider democracies today, are actually ConMons in theory, but just function as democracies, since the king never actually makes a decision against the parliament.
An example of a country that went from ConMon to democracy during the Victoria Timeframe, is Denmark (in which I live). And I'm fairly sure that a lot of the countries in Europe, that still have a monarchy, are still ConMons in theory, but during the Victoria timespan, the king simply got less and less to say, and in the end simply just functioned as a puppet of the government (in lack of better expression). (I'm not totally sure if I'm right here, correct me if not.)
Now with that said, I think you can say that some countries, while not changing their constitution in the Victoria timespan, did still change into a fuctional democracy, only maintaining the ConMon by name, and as such should have the features of a democracy.
Dunno if I'm all wrong, but I know that at least Denmark went from ConMon to Democracy during Victoria.