sync: Process 'control' data separately

sync/engine/resolve_conflicts_command.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sync/engine/resolve_conflicts_command.h"
 
 #include "sync/engine/conflict_resolver.h"
 #include "sync/sessions/session_state.h"
 #include "sync/sessions/sync_session.h"
 #include "sync/syncable/directory.h"
 #include "sync/syncable/write_transaction.h"
 
 namespace csync {
 
 ResolveConflictsCommand::ResolveConflictsCommand() {}
 ResolveConflictsCommand::~ResolveConflictsCommand() {}
 
 std::set<ModelSafeGroup> ResolveConflictsCommand::GetGroupsToChange(
     const sessions::SyncSession& session) const {
-  return session.GetEnabledGroupsWithConflicts();
+  std::set<ModelSafeGroup> groups_with_conflicts =
+      session.GetEnabledGroupsWithConflicts();
+
+  // GROUP_CONTROL conflicts are not handled by this command.
+  groups_with_conflicts.erase(GROUP_CONTROL);
+
+  return groups_with_conflicts;
 }
 
 SyncerError ResolveConflictsCommand::ModelChangingExecuteImpl(
     sessions::SyncSession* session) {
   ConflictResolver* resolver = session->context()->resolver();
   DCHECK(resolver);
 
   syncable::Directory* dir = session->context()->directory();
   sessions::StatusController* status = session->mutable_status_controller();
   const sessions::ConflictProgress* progress = status->conflict_progress();
   if (!progress)
     return SYNCER_OK;  // Nothing to do.
   syncable::WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir);
   const Cryptographer* cryptographer = dir->GetCryptographer(&trans);
   status->update_conflicts_resolved(
       resolver->ResolveConflicts(&trans, cryptographer, *progress, status));
 
   return SYNCER_OK;
 }
 
 }  // namespace csync