[Sync] Allow sync start without sign-in if the local sync backend is on.

components/sync/engine/engine_components_factory_impl.cc

Index: components/sync/engine/engine_components_factory_impl.cc
diff --git a/components/sync/engine/engine_components_factory_impl.cc b/components/sync/engine/engine_components_factory_impl.cc
index d3d3a88057b32d315b66dde205f32543760f1530..61fb158f2e3e9e7084e4cacea30818649032d1a3 100644
--- a/components/sync/engine/engine_components_factory_impl.cc
+++ b/components/sync/engine/engine_components_factory_impl.cc
@@ -28,7 +28,8 @@ EngineComponentsFactoryImpl::~EngineComponentsFactoryImpl() {}
 std::unique_ptr<SyncScheduler> EngineComponentsFactoryImpl::BuildScheduler(
     const std::string& name,
     SyncCycleContext* context,
-    CancelationSignal* cancelation_signal) {
+    CancelationSignal* cancelation_signal,
+    bool local_sync_backend_enabled) {
   std::unique_ptr<BackoffDelayProvider> delay(
       BackoffDelayProvider::FromDefaults());
 
@@ -38,7 +39,8 @@ std::unique_ptr<SyncScheduler> EngineComponentsFactoryImpl::BuildScheduler(
 
   std::unique_ptr<SyncSchedulerImpl> scheduler =
       base::MakeUnique<SyncSchedulerImpl>(name, delay.release(), context,
-                                          new Syncer(cancelation_signal));
+                                          new Syncer(cancelation_signal),
+                                          local_sync_backend_enabled);
   if (switches_.nudge_delay == NudgeDelay::SHORT_NUDGE_DELAY) {
     // Set the default nudge delay to 0 because the default is used as a floor
     // for override values, and we don't want the below override to be ignored.