Delete and try to recreate localstorage database on invalid schema version.

components/leveldb/public/interfaces/leveldb.mojom

 // Copyright 2015 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.
 
 module leveldb.mojom;
 
 import "components/filesystem/public/interfaces/directory.mojom";
 import "mojo/common/unguessable_token.mojom";
 
 enum DatabaseError {
@@ skipping 44 matching lines @@
   // Number of open files that can be used by the DB. (Note: we globally set
   // the default here to 80 instead of leveldb's default 1000 because we don't
   // want to consume all file descriptors. See
   // https://code.google.com/p/chromium/issues/detail?id=227313#c11 for
   // details.)
   int32 max_open_files = 80;
 };
 
 // Service which hands out databases.
 interface LevelDBService {
+  // Open the database with the specified "name" in the specified "directory".
+  // Fails if the database doesn't already exist.
   Open(filesystem.mojom.Directory directory,
        string dbname,
-       LevelDBDatabase& database) => (DatabaseError status);
+       associated LevelDBDatabase& database) => (DatabaseError status);
+
+  // Open the database with the specified "name" in the specified "directory".
   OpenWithOptions(OpenOptions options,
                   filesystem.mojom.Directory directory,
                   string dbname,
-                  LevelDBDatabase& database) => (DatabaseError status);
+                  associated LevelDBDatabase& database) => (DatabaseError status);
 
-  OpenInMemory(LevelDBDatabase& database) => (DatabaseError status);
+  // Opens a database stored purely in memory.
+  OpenInMemory(associated LevelDBDatabase& database) => (DatabaseError status);
+
+  // Destroys the contents of the specified database. Returns OK if the database
+  // already didn't exist.
+  Destroy(filesystem.mojom.Directory directory,
+          string dbname) => (DatabaseError status);
 };
 
 // A leveldb database.
 interface LevelDBDatabase {
   // Basic Interface -------------------------------------------------------
 
   // Sets the database entry for "key" to "value". Returns OK on success.
   Put(array<uint8> key, array<uint8> value) => (DatabaseError status);
 
   // Remove the database entry (if any) for "key".  Returns OK on
@@ skipping 52 matching lines @@
   // Moves forward or backwards in iterator space.
   [Sync]
   IteratorNext(mojo.common.mojom.UnguessableToken iterator)
       => (bool valid, DatabaseError status, array<uint8>? key,
           array<uint8>? value);
   [Sync]
   IteratorPrev(mojo.common.mojom.UnguessableToken iterator)
       => (bool valid, DatabaseError status, array<uint8>? key,
           array<uint8>? value);
 };