[Sync] Refactor sync datatype error handling.

chrome/browser/sync/glue/model_associator.h

Index: chrome/browser/sync/glue/model_associator.h
diff --git a/chrome/browser/sync/glue/model_associator.h b/chrome/browser/sync/glue/model_associator.h
index eaa2a45e3021c159c3e39514b6e73fd937914310..eb65aab428c75f1fb744b3afe93005ebb4460561 100644
--- a/chrome/browser/sync/glue/model_associator.h
+++ b/chrome/browser/sync/glue/model_associator.h
@@ -9,6 +9,8 @@
 #include "base/basictypes.h"
 #include "chrome/browser/sync/syncable/model_type.h"
 
+class SyncError;
+
 namespace sync_api {
 class BaseNode;
 }
@@ -27,10 +29,12 @@ class AssociatorInterface {
   // should be identical and corresponding. Returns true on
   // success. On failure of this step, we should abort the sync
   // operation and report an error to the user.
-  virtual bool AssociateModels() = 0;
+  // TODO(zea): return a SyncError instead of passing one in.
+  virtual bool AssociateModels(SyncError* error) = 0;
 
   // Clears all the associations between the chrome and sync models.
-  virtual bool DisassociateModels() = 0;
+  // TODO(zea): return a SyncError instead of passing one in.
+  virtual bool DisassociateModels(SyncError* error) = 0;
 
   // The has_nodes out parameter is set to true if the sync model has
   // nodes other than the permanent tagged nodes.  The method may