[MERGE] Factor out revision-history synthesis for reuse

[Martin Pool]

On 21 Jun 2006, Robert Collins <robertc at robertcollins.net> wrote:
> I had a case where I need to create a new revision-history recently.
> This patch made it easier:

+1; I'd just query whether the split-out method should both generate and
set it, or just return it?  If it does set the branches history then the
documentation should say so.

-- 
Martin