sync: Process 'control' data separately

chrome/browser/sync/glue/sync_backend_registrar.cc

Index: chrome/browser/sync/glue/sync_backend_registrar.cc
diff --git a/chrome/browser/sync/glue/sync_backend_registrar.cc b/chrome/browser/sync/glue/sync_backend_registrar.cc
index 409bac14951641baf6480ad61efba502caebe57c..443b19decd94eeeb349a5fcd92e204db6c534e1f 100644
--- a/chrome/browser/sync/glue/sync_backend_registrar.cc
+++ b/chrome/browser/sync/glue/sync_backend_registrar.cc
@@ -32,6 +32,8 @@ bool IsOnThreadForGroup(ModelSafeGroup group) {
   switch (group) {
     case GROUP_PASSIVE:
       return false;
+    case GROUP_INTERNAL:
+      return false;
     case GROUP_UI:
       return BrowserThread::CurrentlyOn(BrowserThread::UI);
     case GROUP_DB:
@@ -68,6 +70,7 @@ SyncBackendRegistrar::SyncBackendRegistrar(
   workers_[GROUP_FILE] = new FileModelWorker();
   workers_[GROUP_UI] = ui_worker_;
   workers_[GROUP_PASSIVE] = new PassiveModelWorker(sync_loop_);
+  workers_[GROUP_INTERNAL] = new PassiveModelWorker(sync_loop_);
 
   // Any datatypes that we want the syncer to pull down must be in the
   // routing_info map.  We set them to group passive, meaning that
@@ -133,7 +136,11 @@ syncable::ModelTypeSet SyncBackendRegistrar::ConfigureDataTypes(
     // Add a newly specified data type as GROUP_PASSIVE into the
     // routing_info, if it does not already exist.
     if (routing_info_.count(it.Get()) == 0) {
-      routing_info_[it.Get()] = GROUP_PASSIVE;
+      if (IsInternalType(it.Get())) { 
+        routing_info_[it.Get()] = GROUP_INTERNAL;
+      } else {
+        routing_info_[it.Get()] = GROUP_PASSIVE;
+      }
       newly_added_types.Put(it.Get());
     }
   }