sync: hook up ServerConnectionManager <> SyncerThread2 and tie up more loose ends

chrome/browser/sync/engine/update_applicator.cc

Index: chrome/browser/sync/engine/update_applicator.cc
diff --git a/chrome/browser/sync/engine/update_applicator.cc b/chrome/browser/sync/engine/update_applicator.cc
index 6922c0f12e5540c1a117a7cf96313a784c8b3710..04eca4390567a7275ea9a2e1acd07be58bfbc152 100644
--- a/chrome/browser/sync/engine/update_applicator.cc
+++ b/chrome/browser/sync/engine/update_applicator.cc
@@ -91,10 +91,21 @@ void UpdateApplicator::Advance() {
 }
 
 bool UpdateApplicator::SkipUpdate(const syncable::Entry& entry) {
-  ModelSafeGroup g =
-      GetGroupForModelType(entry.GetServerModelType(), routing_info_);
+  syncable::ModelType type = entry.GetServerModelType();
+  ModelSafeGroup g = GetGroupForModelType(type, routing_info_);
+  // The extra routing_info count check here is to support GetUpdateses for
+  // a subset of the globally enabled types, and not attempt to update items
+  // if their type isn't permitted in the current run.  These would typically
+  // be unapplied items from a previous sync.
   if (g != group_filter_)
     return true;
+  if (g == GROUP_PASSIVE &&
+      !routing_info_.count(type) &&
+      type != syncable::UNSPECIFIED &&
+      type != syncable::TOP_LEVEL_FOLDER) {
+    VLOG(1) << "Skipping update application, type not permitted.";
+    return true;
+  }
   return false;
 }