Don't abuse LevelDBObserver interface to pass GetAll result.

content/browser/leveldb_wrapper_impl.h

 // 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.
 
 #ifndef CONTENT_BROWSER_LEVELDB_WRAPPER_IMPL_H_
 #define CONTENT_BROWSER_LEVELDB_WRAPPER_IMPL_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 85 matching lines @@
            const std::vector<uint8_t>& value,
            const std::string& source,
            const PutCallback& callback) override;
   void Delete(const std::vector<uint8_t>& key,
               const std::string& source,
               const DeleteCallback& callback) override;
   void DeleteAll(const std::string& source,
                  const DeleteAllCallback& callback) override;
   void Get(const std::vector<uint8_t>& key,
            const GetCallback& callback) override;
-  void GetAll(const std::string& source,
-              const GetAllCallback& callback) override;
+  void GetAll(
+      mojom::LevelDBWrapperGetAllCallbackAssociatedPtrInfo complete_callback,
+      const GetAllCallback& callback) override;
 
   void OnConnectionError();
   void LoadMap(const base::Closure& completion_callback);
   void OnLoadComplete(leveldb::mojom::DatabaseError status,
                       std::vector<leveldb::mojom::KeyValuePtr> data);
   void CreateCommitBatchIfNeeded();
   void StartCommitTimer();
   base::TimeDelta ComputeCommitDelay() const;
   void CommitChanges();
   void OnCommitComplete(leveldb::mojom::DatabaseError error);
@@ skipping 16 matching lines @@
   base::WeakPtrFactory<LevelDBWrapperImpl> weak_ptr_factory_;
 
   static bool s_aggressive_flushing_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(LevelDBWrapperImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_LEVELDB_WRAPPER_IMPL_H_