Server directed error handling backend code.

chrome/browser/sync/sessions/sync_session.h

 // Copyright (c) 2011 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.
 
 // A class representing an attempt to synchronize the local syncable data
 // store with a sync server. A SyncSession instance is passed as a stateful
 // bundle to and from various SyncerCommands with the goal of converging the
 // client view of data with that of the server. The commands twiddle with
 // session status in response to events and hiccups along the way, set and
 // query session progress with regards to conflict resolution and applying
@@ skipping 61 matching lines @@
 
     // The client has been instructed to change its sessions commit
     // delay.
     virtual void OnReceivedSessionsCommitDelay(
         const base::TimeDelta& new_delay) = 0;
 
     // The client needs to cease and desist syncing at once.  This occurs when
     // the Syncer detects that the backend store has fundamentally changed or
     // is a different instance altogether (e.g. swapping from a test instance
     // to production, or a global stop syncing operation has wiped the store).
+    // TODO(lipalani) : Replace this function with the one below. This function
+    // stops the current sync cycle and purges the client. In the new model
+    // the former would be done by the |SyncProtocolError| and
+    // the latter(which is an action) would be done in ProfileSyncService
+    // along with the rest of the actions.
     virtual void OnShouldStopSyncingPermanently() = 0;
 
+    // Called for the syncer to respond to the error sent by the server.
+    virtual void OnSyncProtocolError(sessions::SyncSession* session) = 0;
+
    protected:
     virtual ~Delegate() {}
   };
 
   SyncSession(SyncSessionContext* context,
               Delegate* delegate,
               const SyncSourceInfo& source,
               const ModelSafeRoutingInfo& routing_info,
               const std::vector<ModelSafeWorker*>& workers);
   ~SyncSession();
@@ skipping 94 matching lines @@
 
  private:
   SyncSession* session_;
   DISALLOW_COPY_AND_ASSIGN(ScopedSetSessionWriteTransaction);
 };
 
 }  // namespace sessions
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSION_H_