Revert 112178 - [Sync] Make syncer commands avoid posting tasks on threads with no work to do

chrome/browser/sync/engine/process_updates_command.cc

Index: chrome/browser/sync/engine/process_updates_command.cc
===================================================================
--- chrome/browser/sync/engine/process_updates_command.cc	(revision 112317)
+++ chrome/browser/sync/engine/process_updates_command.cc	(working copy)
@@ -22,16 +22,10 @@
 
 using sessions::SyncSession;
 using sessions::StatusController;
-using sessions::UpdateProgress;
 
 ProcessUpdatesCommand::ProcessUpdatesCommand() {}
 ProcessUpdatesCommand::~ProcessUpdatesCommand() {}
 
-std::set<ModelSafeGroup> ProcessUpdatesCommand::GetGroupsToChange(
-    const sessions::SyncSession& session) const {
-  return session.GetEnabledGroupsWithVerifiedUpdates();
-}
-
 bool ProcessUpdatesCommand::ModelNeutralExecuteImpl(SyncSession* session) {
   const GetUpdatesResponse& updates =
       session->status_controller().updates_response().get_updates();