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

components/sync/engine_impl/sync_manager_impl.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 "components/sync/engine_impl/sync_manager_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 209 matching lines @@
                              new_routing_info, ready_task, retry_task);
 
   scheduler_->Start(SyncScheduler::CONFIGURATION_MODE, base::Time());
   scheduler_->ScheduleConfiguration(params);
 }
 
 void SyncManagerImpl::Init(InitArgs* args) {
   CHECK(!initialized_);
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(args->post_factory.get());
-  DCHECK(!args->credentials.account_id.empty());
-  DCHECK(!args->credentials.sync_token.empty());
-  DCHECK(!args->credentials.scope_set.empty());
+  if (!args->enable_local_sync_backend) {
+    DCHECK(!args->credentials.account_id.empty());
+    DCHECK(!args->credentials.sync_token.empty());
+    DCHECK(!args->credentials.scope_set.empty());
+  }
   DCHECK(args->cancelation_signal);
   DVLOG(1) << "SyncManager starting Init...";
 
   weak_handle_this_ = MakeWeakHandle(weak_ptr_factory_.GetWeakPtr());
 
   change_delegate_ = args->change_delegate;
 
   AddObserver(&js_sync_manager_observer_);
   SetJsEventHandler(args->event_handler);
 
@@ skipping 81 matching lines @@
   // Build a SyncCycleContext and store the worker in it.
   DVLOG(1) << "Sync is bringing up SyncCycleContext.";
   std::vector<SyncEngineEventListener*> listeners;
   listeners.push_back(&allstatus_);
   listeners.push_back(this);
   cycle_context_ = args->engine_components_factory->BuildContext(
       connection_manager_.get(), directory(), args->extensions_activity,
       listeners, &debug_info_event_listener_, model_type_registry_.get(),
       args->invalidator_client_id);
   scheduler_ = args->engine_components_factory->BuildScheduler(
-      name_, cycle_context_.get(), args->cancelation_signal);
+      name_, cycle_context_.get(), args->cancelation_signal,
+      args->enable_local_sync_backend);
 
   scheduler_->Start(SyncScheduler::CONFIGURATION_MODE, base::Time());
 
   initialized_ = true;
 
-  net::NetworkChangeNotifier::AddIPAddressObserver(this);
-  net::NetworkChangeNotifier::AddConnectionTypeObserver(this);
-  observing_network_connectivity_changes_ = true;
+  if (!args->enable_local_sync_backend) {
+    net::NetworkChangeNotifier::AddIPAddressObserver(this);
+    net::NetworkChangeNotifier::AddConnectionTypeObserver(this);
+    observing_network_connectivity_changes_ = true;
 
-  UpdateCredentials(args->credentials);
+    UpdateCredentials(args->credentials);
+  } else {
+    scheduler_->OnCredentialsUpdated();
+  }
 
   NotifyInitializationSuccess();
 }
 
 void SyncManagerImpl::NotifyInitializationSuccess() {
   for (auto& observer : observers_) {
     observer.OnInitializationComplete(
         MakeWeakHandle(weak_ptr_factory_.GetWeakPtr()),
         MakeWeakHandle(debug_info_event_listener_.GetWeakPtr()), true,
         InitialSyncEndedTypes());
@@ skipping 667 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   cycle_context_->set_cookie_jar_mismatch(account_mismatch);
   cycle_context_->set_cookie_jar_empty(empty_jar);
 }
 
 void SyncManagerImpl::OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd) {
   directory()->OnMemoryDump(pmd);
 }
 
 }  // namespace syncer