Port IndexedDB open() and database callbacks to Mojo.

third_party/WebKit/public/platform/modules/indexeddb/indexed_db.mojom

+// Copyright 2016 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 indexed_db.mojom;
+
+import "url/mojo/origin.mojom";
+
+struct ErrorInfo {
+  int16 code;
+  string message;
+};
+
+// An interface implemented by the client that exists for the lifetime of an
+// open database connection. Used by the server to send unsolicited messages to
+// the client.
+interface DatabaseClient {
+  OnTransactionAborted(int64 host_transaction_id, ErrorInfo error);
+  OnTransactionCompleted(int64 host_transaction_id);
+  OnForcedClosed();
+  OnVersionChange(int64 old_version, int64 new_version);
+};
+
+interface DatabaseFactory {
+  Open(string name, int64 version, int64 transaction_id,
+       url.mojom.Origin origin, associated DatabaseClient client, int64 thread_id,
+       int64 callbacks_id);
+};