[Sync] Set HasCustomGroupsToChange() to true for ProcessUpdatesCommand

Follow-up to 113090 to see which ModelChangingSyncerCommand triggers
a perf regression.

BUG=97832
TEST=

Review URL: http://codereview.chromium.org/8822017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@114090 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/sync/engine/process_updates_command.cc

@@ -28,8 +28,7 @@ ProcessUpdatesCommand::ProcessUpdatesCommand() {}
 ProcessUpdatesCommand::~ProcessUpdatesCommand() {}
 
 bool ProcessUpdatesCommand::HasCustomGroupsToChange() const {
-  // TODO(akalin): Set to true.
-  return false;
+  return true;
 }
 
 std::set<ModelSafeGroup> ProcessUpdatesCommand::GetGroupsToChange(