[Sync] Refactor sync datatype error handling.

chrome/browser/sync/glue/session_model_associator.h

Index: chrome/browser/sync/glue/session_model_associator.h
diff --git a/chrome/browser/sync/glue/session_model_associator.h b/chrome/browser/sync/glue/session_model_associator.h
index 5423f278c23bb96966bf6653bdb4814d329f88ac..0f2d244f56c5890ab389c54b73058e65765c5842 100644
--- a/chrome/browser/sync/glue/session_model_associator.h
+++ b/chrome/browser/sync/glue/session_model_associator.h
@@ -116,7 +116,7 @@ class SessionModelAssociator
   // with local client data. Processes/reuses any sync nodes owned by this
   // client and creates any further sync nodes needed to store local header and
   // tab info.
-  virtual bool AssociateModels();
+  virtual bool AssociateModels(SyncError* error);
 
   // Initializes the given sync node from the given chrome node id.
   // Returns false if no sync node was found for the given chrome node id or
@@ -126,7 +126,7 @@ class SessionModelAssociator
 
   // Clear local sync data buffers. Does not delete sync nodes to avoid
   // tombstones. TODO(zea): way to eventually delete orphaned nodes.
-  virtual bool DisassociateModels();
+  virtual bool DisassociateModels(SyncError* error);
 
   // Returns the tag used to uniquely identify this machine's session in the
   // sync model.