Use a two-part data format version in IndexedDB metadata.

content/browser/indexed_db/indexed_db_dispatcher_host.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_DISPATCHER_HOST_H_
 #define CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_DISPATCHER_HOST_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/optional.h"
 #include "content/browser/blob_storage/chrome_blob_storage_context.h"
 #include "content/common/indexed_db/indexed_db.mojom.h"
 #include "content/public/browser/browser_thread.h"
 #include "mojo/public/cpp/bindings/associated_binding_set.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "storage/browser/blob/blob_data_handle.h"
 
 namespace url {
 class Origin;
 }
@@ skipping 29 matching lines @@
   void DropBlobData(const std::string& uuid);
 
  private:
   // Friends to enable OnDestruct() delegation.
   friend class BrowserThread;
   friend class base::DeleteHelper<IndexedDBDispatcherHost>;
 
   ~IndexedDBDispatcherHost() override;
 
   // indexed_db::mojom::Factory implementation:
+  void Configure(
+      const IndexedDBDataFormatVersion& client_data_format_version) override;
   void GetDatabaseNames(
       ::indexed_db::mojom::CallbacksAssociatedPtrInfo callbacks_info,
       const url::Origin& origin) override;
   void Open(::indexed_db::mojom::CallbacksAssociatedPtrInfo callbacks_info,
             ::indexed_db::mojom::DatabaseCallbacksAssociatedPtrInfo
                 database_callbacks_info,
             const url::Origin& origin,
             const base::string16& name,
             int64_t version,
             int64_t transaction_id) override;
   void DeleteDatabase(
       ::indexed_db::mojom::CallbacksAssociatedPtrInfo callbacks_info,
       const url::Origin& origin,
       const base::string16& name,
       bool force_close) override;
 
+  void ConfigureOnIDBThread(
+      const IndexedDBDataFormatVersion& client_data_format_version);
   void GetDatabaseNamesOnIDBThread(scoped_refptr<IndexedDBCallbacks> callbacks,
                                    const url::Origin& origin);
   void OpenOnIDBThread(
       scoped_refptr<IndexedDBCallbacks> callbacks,
       scoped_refptr<IndexedDBDatabaseCallbacks> database_callbacks,
       const url::Origin& origin,
       const base::string16& name,
       int64_t version,
       int64_t transaction_id);
   void DeleteDatabaseOnIDBThread(scoped_refptr<IndexedDBCallbacks> callbacks,
@@ skipping 10 matching lines @@
   // Maps blob uuid to a pair (handle, ref count). Entry is added and/or count
   // is incremented in HoldBlobData(), and count is decremented and/or entry
   // removed in DropBlobData().
   std::map<std::string,
            std::pair<std::unique_ptr<storage::BlobDataHandle>, int>>
       blob_data_handle_map_;
 
   // Used to set file permissions for blob storage.
   const int ipc_process_id_;
 
+  // The reported data format version supported by the client, used when opening
+  // the backing store. Only accessed on the IDB thread.
+  base::Optional<IndexedDBDataFormatVersion> client_data_format_version_;
+
   mojo::AssociatedBindingSet<::indexed_db::mojom::Factory> bindings_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(IndexedDBDispatcherHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_INDEXED_DB_INDEXED_DB_DISPATCHER_HOST_H_