Create meta table atomically.

chrome/browser/history/download_database.h

Index: chrome/browser/history/download_database.h
diff --git a/chrome/browser/history/download_database.h b/chrome/browser/history/download_database.h
index 367f9b2d8ed1035b8f922e9c64b44ca830cc009e..541f4bbf93d24aa71649602ccd9f40aa52c1b5d6 100644
--- a/chrome/browser/history/download_database.h
+++ b/chrome/browser/history/download_database.h
@@ -64,6 +64,9 @@ class DownloadDatabase {
   // Returns the database for the functions in this interface.
   virtual sql::Connection& GetDB() = 0;
 
+  // Returns the meta-table object for the functions in this interface.
+  virtual sql::MetaTable& GetMetaTable() = 0;
+
   // Creates the downloads table if needed.
   bool InitDownloadTable();
 
@@ -82,7 +85,6 @@ class DownloadDatabase {
 
   int next_id_;
   int next_db_handle_;
-  sql::MetaTable meta_table_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadDatabase);
 };