Revert 94128 - [Sync] Refactor sync datatype error handling.

chrome/browser/sync/api/syncable_service.h

Index: chrome/browser/sync/api/syncable_service.h
===================================================================
--- chrome/browser/sync/api/syncable_service.h	(revision 94142)
+++ chrome/browser/sync/api/syncable_service.h	(working copy)
@@ -12,7 +12,6 @@
 #include "chrome/browser/sync/syncable/model_type.h"
 #include "chrome/browser/sync/api/sync_change_processor.h"
 #include "chrome/browser/sync/api/sync_data.h"
-#include "chrome/browser/sync/api/sync_error.h"
 
 class SyncData;
 
@@ -26,10 +25,7 @@
   // two. After this, the SyncableService's local data should match the server
   // data, and the service should be ready to receive and process any further
   // SyncChange's as they occur.
-  // Returns: A default SyncError (IsSet() == false) if no errors were
-  //          encountered, and a filled SyncError (IsSet() == true)
-  //          otherwise.
-  virtual SyncError MergeDataAndStartSyncing(
+  virtual bool MergeDataAndStartSyncing(
       syncable::ModelType type,
       const SyncDataList& initial_sync_data,
       SyncChangeProcessor* sync_processor) = 0;
@@ -44,10 +40,7 @@
 
   // SyncChangeProcessor interface.
   // Process a list of new SyncChanges and update the local data as necessary.
-  // Returns: A default SyncError (IsSet() == false) if no errors were
-  //          encountered, and a filled SyncError (IsSet() == true)
-  //          otherwise.
-  virtual SyncError ProcessSyncChanges(
+  virtual void ProcessSyncChanges(
       const tracked_objects::Location& from_here,
       const SyncChangeList& change_list) OVERRIDE = 0;