[Sync] Move ModelType and related classes to 'syncer' namespace

sync/syncable/mutable_entry.cc

Index: sync/syncable/mutable_entry.cc
diff --git a/sync/syncable/mutable_entry.cc b/sync/syncable/mutable_entry.cc
index 95c021df30c894d60f573825ecacdb8367602afa..c61bcb3dbd747d1bf566c4f048ab989f6b5f5e29 100644
--- a/sync/syncable/mutable_entry.cc
+++ b/sync/syncable/mutable_entry.cc
@@ -232,7 +232,7 @@ bool MutableEntry::Put(ProtoField field,
     if (update_unapplied_updates_index) {
       // Remove ourselves from unapplied_update_metahandles with our
       // old server type.
-      const syncable::ModelType old_server_type =
+      const syncer::ModelType old_server_type =
           kernel_->GetServerModelType();
       const int64 metahandle = kernel_->ref(META_HANDLE);
       size_t erase_count =
@@ -247,7 +247,7 @@ bool MutableEntry::Put(ProtoField field,
     if (update_unapplied_updates_index) {
       // Add ourselves back into unapplied_update_metahandles with our
       // new server type.
-      const syncable::ModelType new_server_type =
+      const syncer::ModelType new_server_type =
           kernel_->GetServerModelType();
       const int64 metahandle = kernel_->ref(META_HANDLE);
       dir()->kernel_->unapplied_update_metahandles[new_server_type]