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

components/sync/engine_impl/sync_scheduler_impl.h

 // Copyright 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.
 
 #ifndef COMPONENTS_SYNC_ENGINE_IMPL_SYNC_SCHEDULER_IMPL_H_
 #define COMPONENTS_SYNC_ENGINE_IMPL_SYNC_SCHEDULER_IMPL_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 23 matching lines @@
 class BackoffDelayProvider;
 struct ModelNeutralState;
 
 class SyncSchedulerImpl : public SyncScheduler, public base::NonThreadSafe {
  public:
   // |name| is a display string to identify the syncer thread.  Takes
   // |ownership of |syncer| and |delay_provider|.
   SyncSchedulerImpl(const std::string& name,
                     BackoffDelayProvider* delay_provider,
                     SyncCycleContext* context,
-                    Syncer* syncer);
+                    Syncer* syncer,
+                    bool local_sync_backend_enabled);

[Nicolas Zea, 2016/12/15 00:37:28]

nit: how about renaming this to ignore_auth_credentials or something like that,
to make it more clear what behavior this is controlling. It seems like a
layering violation to be exposing the backend state here.

This also applies to SyncManager and the other layers below PSS that don't
really care what kind of backend there is.

[pastarmovj, 2016/12/16 17:04:48]

Done.

 
   // Calls Stop().
   ~SyncSchedulerImpl() override;
 
   void Start(Mode mode, base::Time last_poll_time) override;
   void ScheduleConfiguration(const ConfigurationParams& params) override;
   void ScheduleClearServerData(const ClearParams& params) override;
   void Stop() override;
   void ScheduleLocalNudge(
       ModelTypeSet types,
@@ skipping 230 matching lines @@
   // time TrySyncCycleJobImpl is called. CANARY_PRIORITY allows syncer to run
   // even if scheduler is in exponential backoff. This is needed for events that
   // have chance of resolving previous error (e.g. network connection change
   // after NETWORK_UNAVAILABLE error).
   // It is reset back to NORMAL_PRIORITY on every call to TrySyncCycleJobImpl.
   JobPriority next_sync_cycle_job_priority_;
 
   // One-shot timer for scheduling GU retry according to delay set by server.
   base::OneShotTimer retry_timer_;
 
+  // Whether the local file based sync backend should be enabled. Dictates if
+  // the sheduler should wait for authentication to happen or not.
+  bool local_sync_backend_enabled_;
+
   base::WeakPtrFactory<SyncSchedulerImpl> weak_ptr_factory_;
 
   // A second factory specially for weak_handle_this_, to allow the handle
   // to be const and alleviate threading concerns.
   base::WeakPtrFactory<SyncSchedulerImpl> weak_ptr_factory_for_weak_handle_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncSchedulerImpl);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_IMPL_SYNC_SCHEDULER_IMPL_H_