[Sync] Refactor sync datatype error handling.

chrome/browser/sync/glue/generic_change_processor.h

Index: chrome/browser/sync/glue/generic_change_processor.h
diff --git a/chrome/browser/sync/glue/generic_change_processor.h b/chrome/browser/sync/glue/generic_change_processor.h
index d3176e53d62c3bbec8ee77bd4a05306606a920a1..4864360b37dda056330b072a1080e713e9df63f0 100644
--- a/chrome/browser/sync/glue/generic_change_processor.h
+++ b/chrome/browser/sync/glue/generic_change_processor.h
@@ -45,12 +45,13 @@ class GenericChangeProcessor : public ChangeProcessor,
   virtual void CommitChangesFromSyncModel() OVERRIDE;
 
   // SyncChangeProcessor implementation.
-  virtual void ProcessSyncChanges(const tracked_objects::Location& from_here,
-                                  const SyncChangeList& change_list) OVERRIDE;
+  virtual SyncError ProcessSyncChanges(
+      const tracked_objects::Location& from_here,
+      const SyncChangeList& change_list) OVERRIDE;
 
   // Fills |current_sync_data| with all the syncer data for the specified type.
-  virtual bool GetSyncDataForType(syncable::ModelType type,
-                                  SyncDataList* current_sync_data);
+  virtual SyncError GetSyncDataForType(syncable::ModelType type,
+                                       SyncDataList* current_sync_data);
 
   // Generic versions of AssociatorInterface methods. Called by
   // SyncableServiceAdapter.