Pref service: Batch pref updates.

services/preferences/public/cpp/persistent_pref_store_client.h

 // Copyright 2017 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 SERVICES_PREFERENCES_PUBLIC_CPP_PERSISTENT_PREF_STORE_CLIENT_H_
 #define SERVICES_PREFERENCES_PUBLIC_CPP_PERSISTENT_PREF_STORE_CLIENT_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 48 matching lines @@
  protected:
   // base::RefCounted<PrefStore>:
   ~PersistentPrefStoreClient() override;
 
  private:
   void OnConnect(mojom::PersistentPrefStoreConnectionPtr connection,
                  std::unordered_map<PrefValueStore::PrefStoreType,
                                     prefs::mojom::PrefStoreConnectionPtr>
                      other_pref_stores);
 
+  void QueueWrite(const std::string& key, uint32_t flags);
+  void FlushPendingWrites();
+
   mojom::PrefStoreConnectorPtr connector_;
   scoped_refptr<PrefRegistry> pref_registry_;
   bool read_only_ = false;
   PrefReadError read_error_ = PersistentPrefStore::PREF_READ_ERROR_NONE;
   mojom::PersistentPrefStorePtr pref_store_;
+  std::map<std::string, uint32_t> pending_writes_;
 
   std::unique_ptr<ReadErrorDelegate> error_delegate_;
   std::vector<PrefValueStore::PrefStoreType> already_connected_types_;
 
+  base::WeakPtrFactory<PersistentPrefStoreClient> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(PersistentPrefStoreClient);
 };
 
 }  // namespace prefs
 
 #endif  // SERVICES_PREFERENCES_PUBLIC_CPP_PERSISTENT_PREF_STORE_CLIENT_H_