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

chrome/browser/profiles/profile.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 "chrome/browser/profiles/profile.h"
 
 #include <string>
 
 #include "build/build_config.h"
 #include "chrome/browser/chrome_notification_types.h"
@@ skipping 193 matching lines @@
 bool Profile::IsNewProfile() {
   // The profile has been shut down if the prefs were loaded from disk, unless
   // first-run autoimport wrote them and reloaded the pref service.
   // TODO(crbug.com/660346): revisit this when crbug.com/22142 (unifying the
   // profile import code) is fixed.
   return GetOriginalProfile()->GetPrefs()->GetInitializationStatus() ==
       PrefService::INITIALIZATION_STATUS_CREATED_NEW_PREF_STORE;
 }
 
 bool Profile::IsSyncAllowed() {
-  if (ProfileSyncServiceFactory::HasProfileSyncService(this)) {
+  if (ProfileSyncServiceFactory::HasProfileSyncService(this))
     return ProfileSyncServiceFactory::GetForProfile(this)->IsSyncAllowed();
-  }
 
   // No ProfileSyncService created yet - we don't want to create one, so just
   // infer the accessible state by looking at prefs/command line flags.
   syncer::SyncPrefs prefs(GetPrefs());
   return browser_sync::ProfileSyncService::IsSyncAllowedByFlag() &&
          !prefs.IsManaged();
 }
 
+bool Profile::IsLocalSyncEnabled() {

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

Do we really need this exposed here? Can we just have the callsites depend on
HasProfileSyncService directly?

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

As suggested reverted this change.

+  if (ProfileSyncServiceFactory::HasProfileSyncService(this))
+    return ProfileSyncServiceFactory::GetForProfile(this)->IsLocalSyncEnabled();
+
+  // No ProfileSyncService created yet - we don't want to create one, so just
+  // infer the accessible state by looking at prefs/command line flags.
+  syncer::SyncPrefs prefs(GetPrefs());
+  return prefs.IsLocalSyncEnabled();
+}
+
 void Profile::MaybeSendDestroyedNotification() {
   if (!sent_destroyed_notification_) {
     sent_destroyed_notification_ = true;
 
     NotifyWillBeDestroyed(this);
     content::NotificationService::current()->Notify(
         chrome::NOTIFICATION_PROFILE_DESTROYED,
         content::Source<Profile>(this),
         content::NotificationService::NoDetails());
   }
 }
 
 bool ProfileCompare::operator()(Profile* a, Profile* b) const {
   DCHECK(a && b);
   if (a->IsSameProfile(b))
     return false;
   return a->GetOriginalProfile() < b->GetOriginalProfile();
 }
 
 double Profile::GetDefaultZoomLevelForProfile() {
   return GetDefaultStoragePartition(this)
       ->GetHostZoomMap()
       ->GetDefaultZoomLevel();
 }