Update from https://crrev.com/309415

net/disk_cache/blockfile/storage_block.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.
 
 // See net/disk_cache/disk_cache.h for the public interface.
 
 #ifndef NET_DISK_CACHE_BLOCKFILE_STORAGE_BLOCK_H_
 #define NET_DISK_CACHE_BLOCKFILE_STORAGE_BLOCK_H_
 
 #include "net/disk_cache/blockfile/addr.h"
@@ skipping 16 matching lines @@
 //    ModifySomething(b.Data());
 //    // Data modified on the previous call will be saved by b's destructor.
 //    b.set_modified();
 template<typename T>
 class StorageBlock : public FileBlock {
  public:
   StorageBlock(MappedFile* file, Addr address);
   virtual ~StorageBlock();
 
   // FileBlock interface.
-  virtual void* buffer() const;
-  virtual size_t size() const;
-  virtual int offset() const;
+  void* buffer() const override;
+  size_t size() const override;
+  int offset() const override;
 
   // Allows the overide of dummy values passed on the constructor.
   bool LazyInit(MappedFile* file, Addr address);
 
   // Sets the internal storage to share the memory provided by other instance.
   void SetData(T* other);
 
   // Deletes the data, even if it was modified and not saved. This object must
   // own the memory buffer (it cannot be shared).
   void Discard();
@@ skipping 38 matching lines @@
   bool modified_;
   bool own_data_;  // Is data_ owned by this object or shared with someone else.
   bool extended_;  // Used to store an entry of more than one block.
 
   DISALLOW_COPY_AND_ASSIGN(StorageBlock);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_BLOCKFILE_STORAGE_BLOCK_H_