Reland: "Sync: Support multiple setup UIs."

ios/chrome/browser/sync/sync_setup_service.cc

Index: ios/chrome/browser/sync/sync_setup_service.cc
diff --git a/ios/chrome/browser/sync/sync_setup_service.cc b/ios/chrome/browser/sync/sync_setup_service.cc
index de1d45f9306fc64a3ba14ec38c32f804bf8a13b3..4bf3b9793381e26edb9838abfa748190483b4ab1 100644
--- a/ios/chrome/browser/sync/sync_setup_service.cc
+++ b/ios/chrome/browser/sync/sync_setup_service.cc
@@ -58,7 +58,7 @@ bool SyncSetupService::IsDataTypeEnabled(syncer::ModelType datatype) const {
 
 void SyncSetupService::SetDataTypeEnabled(syncer::ModelType datatype,
                                           bool enabled) {
-  sync_service_->SetSetupInProgress(true);
+  sync_blocker_ = sync_service_->GetSetupInProgressHandle();
   syncer::ModelTypeSet types = GetDataTypes();
   if (enabled)
     types.Put(datatype);
@@ -100,7 +100,7 @@ bool SyncSetupService::IsSyncingAllDataTypes() const {
 }
 
 void SyncSetupService::SetSyncingAllDataTypes(bool sync_all) {
-  sync_service_->SetSetupInProgress(true);
+  sync_blocker_ = sync_service_->GetSetupInProgressHandle();
   if (sync_all && !IsSyncEnabled())
     SetSyncEnabled(true);
   sync_service_->OnUserChoseDatatypes(
@@ -171,7 +171,7 @@ void SyncSetupService::PrepareForFirstSyncSetup() {
   // |PrepareForFirstSyncSetup| should always be called while the user is signed
   // out. At that time, sync setup is not completed.
   DCHECK(!sync_service_->IsFirstSetupComplete());
-  sync_service_->SetSetupInProgress(true);
+  sync_blocker_ = sync_service_->GetSetupInProgressHandle();
 }
 
 void SyncSetupService::CommitChanges() {
@@ -183,7 +183,7 @@ void SyncSetupService::CommitChanges() {
     }
   }
 
-  sync_service_->SetSetupInProgress(false);
+  sync_blocker_.reset();
 }
 
 bool SyncSetupService::HasUncommittedChanges() {
@@ -192,7 +192,7 @@ bool SyncSetupService::HasUncommittedChanges() {
 
 void SyncSetupService::SetSyncEnabledWithoutChangingDatatypes(
     bool sync_enabled) {
-  sync_service_->SetSetupInProgress(true);
+  sync_blocker_ = sync_service_->GetSetupInProgressHandle();
   if (sync_enabled) {
     sync_service_->RequestStart();
   } else {