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 45da9afb4d0499617db01308b41a54a78b3f59fd..96a2d7e79cd16ba18010faf90f7b4a1e4eb1d6fd 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(csync::ModelSafeGroup group) {
   switch (group) {
     case csync::GROUP_PASSIVE:
       return false;
+    case csync::GROUP_CONTROL:
+      return false;
     case csync::GROUP_UI:
       return BrowserThread::CurrentlyOn(BrowserThread::UI);
     case csync::GROUP_DB:
@@ -68,6 +70,7 @@ SyncBackendRegistrar::SyncBackendRegistrar(
   workers_[csync::GROUP_FILE] = new FileModelWorker();
   workers_[csync::GROUP_UI] = ui_worker_;
   workers_[csync::GROUP_PASSIVE] = new csync::PassiveModelWorker(sync_loop_);
+  workers_[csync::GROUP_CONTROL] = new csync::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
@@ -75,7 +78,11 @@ SyncBackendRegistrar::SyncBackendRegistrar(
   // models.
   for (syncable::ModelTypeSet::Iterator it = initial_types.First();
        it.Good(); it.Inc()) {
-    routing_info_[it.Get()] = csync::GROUP_PASSIVE;
+    if (IsInternalType(it.Get())) {
+      routing_info_[it.Get()] = csync::GROUP_CONTROL;
+    } else {
+      routing_info_[it.Get()] = csync::GROUP_PASSIVE;
+    }
   }
 
   HistoryService* history_service = profile->GetHistoryService(
@@ -133,7 +140,11 @@ syncable::ModelTypeSet SyncBackendRegistrar::ConfigureDataTypes(
     // Add a newly specified data type as csync::GROUP_PASSIVE into the
     // routing_info, if it does not already exist.
     if (routing_info_.count(it.Get()) == 0) {
-      routing_info_[it.Get()] = csync::GROUP_PASSIVE;
+      if (IsInternalType(it.Get())) {
+        routing_info_[it.Get()] = csync::GROUP_CONTROL;
+      } else {
+        routing_info_[it.Get()] = csync::GROUP_PASSIVE;
+      }
       newly_added_types.Put(it.Get());
     }
   }