[sql] RecoverDatabase() deletes SQLITE_NOTADB databases.

sql/recovery.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SQL_RECOVERY_H_
 #define SQL_RECOVERY_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 146 matching lines @@
 
   // Attempt to recover the database by creating a new database with schema from
   // |db|, then copying over as much data as possible.  After this call, the
   // |db| handle will be poisoned (though technically remaining open) so that
   // future calls will return errors until the handle is re-opened.
   //
   // If a corrupt database contains tables without unique indices, the resulting
   // table may contain duplication.  If this is not acceptable, the client
   // should use the manual process as described in the example at the top of the
   // file, cleaning up data at the appropriate points.
+  //
+  // In case of SQLITE_NOTADB, the database is deemed unrecoverable and deleted.
   static void RecoverDatabase(Connection* db, const base::FilePath& db_path);
 
   // Returns true for SQLite errors which RecoverDatabase() can plausibly fix.
   // This does not guarantee that RecoverDatabase() will successfully recover
   // the database.
   static bool ShouldRecover(int extended_error);
 
  private:
   explicit Recovery(Connection* connection);
 
@@ skipping 15 matching lines @@
 
   Connection* db_;         // Original database connection.
   Connection recover_db_;  // Recovery connection.
 
   DISALLOW_COPY_AND_ASSIGN(Recovery);
 };
 
 }  // namespace sql
 
 #endif  // SQL_RECOVERY_H_