If we consider a solar cell with top of the line 15% efficiency and use that to charge our electric car, of course the overall efficiency takes a sharp drop. But I don't think it is useful to include the efficiency of the solar cell in the calculation here. After all, the 85% that the solar cell couldn't convert into electricity aren't useable by any other way known to man either; the loss is neither here nor there because we can't do better utilizing the sun than with current gen solar panels.
If you consider, however, that oil refineries consume significant amounts of electricity (from the grid, no electricity equivalents here) to refine oil into something our cars can use, that is certainly a factor we need to include in the efficiency calculation for gasoline powered cars. That electricity could have been used to power an electric car, after all, so there was an actual loss here.
Unless you're talking about converting natural gas or coal directly to hydrogen, which is just as asinine.
You're comparing apples and oranges. That electricity isn't generated via a particularly efficient mechanism after all.