Revert of [Sync] Make directory types registration explicit in ModelTypeRegistry

components/sync/engine_impl/sync_scheduler_impl.cc

Index: components/sync/engine_impl/sync_scheduler_impl.cc
diff --git a/components/sync/engine_impl/sync_scheduler_impl.cc b/components/sync/engine_impl/sync_scheduler_impl.cc
index 09a873c896c41687c6d9e73be854d4cb7006e6cf..69559b513ea342ed2c36229a5aea643c48e91bb8 100644
--- a/components/sync/engine_impl/sync_scheduler_impl.cc
+++ b/components/sync/engine_impl/sync_scheduler_impl.cc
@@ -100,10 +100,12 @@
 ConfigurationParams::ConfigurationParams(
     const sync_pb::GetUpdatesCallerInfo::GetUpdatesSource& source,
     ModelTypeSet types_to_download,
+    const ModelSafeRoutingInfo& routing_info,
     const base::Closure& ready_task,
     const base::Closure& retry_task)
     : source(source),
       types_to_download(types_to_download),
+      routing_info(routing_info),
       ready_task(ready_task),
       retry_task(retry_task) {
   DCHECK(!ready_task.is_null());
@@ -268,6 +270,25 @@
     observer.OnSyncCycleEvent(event);
 }
 
+namespace {
+
+// Helper to extract the routing info corresponding to types in
+// |types_to_download| from |current_routes|.
+void BuildModelSafeParams(ModelTypeSet types_to_download,
+                          const ModelSafeRoutingInfo& current_routes,
+                          ModelSafeRoutingInfo* result_routes) {
+  for (ModelTypeSet::Iterator iter = types_to_download.First(); iter.Good();
+       iter.Inc()) {
+    ModelType type = iter.Get();
+    ModelSafeRoutingInfo::const_iterator route = current_routes.find(type);
+    DCHECK(route != current_routes.end());
+    ModelSafeGroup group = route->second;
+    (*result_routes)[type] = group;
+  }
+}
+
+}  // namespace.
+
 void SyncSchedulerImpl::ScheduleConfiguration(
     const ConfigurationParams& params) {
   DCHECK(CalledOnValidThread());
@@ -280,6 +301,11 @@
   // Only one configuration is allowed at a time. Verify we're not waiting
   // for a pending configure job.
   DCHECK(!pending_configure_params_);
+
+  ModelSafeRoutingInfo restricted_routes;
+  BuildModelSafeParams(params.types_to_download, params.routing_info,
+                       &restricted_routes);
+  cycle_context_->SetRoutingInfo(restricted_routes);
 
   // Only reconfigure if we have types to download.
   if (!params.types_to_download.Empty()) {