Fix downloads db state=3 corruption using version=23

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 502610b169fc2b0b0877a188a1f2dbba21f55425..f5e18bdfbbf052c255c5a7aec5f5884b0b4143b8 100644
--- a/chrome/browser/history/download_database.h
+++ b/chrome/browser/history/download_database.h
@@ -70,6 +70,11 @@ class DownloadDatabase {
   // Returns the meta-table object for the functions in this interface.
   virtual sql::MetaTable& GetMetaTable() = 0;
 
+  // Returns true if able to successfully rewrite the invalid values for the
+  // |state| field from 3 to 4. Returns false if there was an error fixing the
+  // database. See http://crbug.com/140687
+  bool MigrateDownloadsState();
+
   // Creates the downloads table if needed.
   bool InitDownloadTable();