Remove single direction conflict set code

Remove single direction conflict set code

This code was intended to operate on conflict sets that consist solely
of changes from the server.  However, we can never detect these kinds of
conflict sets because our conflict set detection code assumes that the
server never sends us an invalid set of changes; all conflict sets must
be cause, at least in part, by local changes.

This change also deletes various private and hidden functions that were
used only by the single direction conflict set code.  This reduced the
BuildAndProcessConflictSetsCommand::ExecuteImpl() into a single function
call, which I inlined.

Also removed in this change is the conflict_sets_built() flag.  The
single direction conflict set processing code was the only place where
its value was "set".  It seems that the logic that relied on it in
syncer.cc was reversed.  We only processed conflicts if
!conflict_sets_built(), which is the opposite of what the documentation
claims.  Fortunately, its value was always false (because there were no
single direction conflict sets) so we always processed conflicts.

Finally, this CL includes one unrelated change: it removes
BuildAndProcessConflictSetsCommand::MergeSetsForNameClash().  That
function is not defined anywhere, so I decided to remove its
declaration.

BUG=107816
TEST=


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=119507

[rlarocque, 2012-01-12 22:39:15]

Take your time in reviewing this.  I've got plenty of other changes to commit
before I get around to this one.

If the first paragraph of the commit message seems a bit too hand-wavy, refer to
comment #2 on crbug.com/107816 for a more technical (and lengthy) discussion of
why this code is unreachable.

[tim (not reviewing), 2012-01-24 05:01:16]

Nice patch.  I looked at this for a while, and your logic definitely seems
sound.  LGTM!

[commit-bot: I haz the power, 2012-01-27 18:58:33]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rlarocque@chromium.org/9107055/10001

[commit-bot: I haz the power, 2012-01-27 23:05:46]

Change committed as 119507