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

chrome/browser/profiles/profile.h

 // 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.
 
 // This class gathers state related to a single user profile.
 
 #ifndef CHROME_BROWSER_PROFILES_PROFILE_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_H_
 
 #include <string>
@@ skipping 299 matching lines @@
   }
 
   // Returns whether the profile is new.  A profile is new if the browser has
   // not been shut down since the profile was created.
   bool IsNewProfile();
 
   // Checks whether sync is configurable by the user. Returns false if sync is
   // disallowed by the command line or controlled by configuration management.
   bool IsSyncAllowed();
 
+  // Checks whether sync has been enabled in local backend mode.
+  bool IsLocalSyncEnabled();
+
   // Send NOTIFICATION_PROFILE_DESTROYED for this Profile, if it has not
   // already been sent. It is necessary because most Profiles are destroyed by
   // ProfileDestroyer, but in tests, some are not.
   void MaybeSendDestroyedNotification();
 
   // Creates an OffTheRecordProfile which points to this Profile.
   Profile* CreateOffTheRecordProfile();
 
   // Convenience method to retrieve the default zoom level for the default
   // storage partition.
@@ skipping 28 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(Profile);
 };
 
 // The comparator for profile pointers as key in a map.
 struct ProfileCompare {
   bool operator()(Profile* a, Profile* b) const;
 };
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_H_