Remove unused blink::WebStorageArea::memoryBytesUsedByCache().

content/renderer/dom_storage/webstoragearea_impl.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_RENDERER_DOM_STORAGE_WEBSTORAGEAREA_IMPL_H_
 #define CONTENT_RENDERER_DOM_STORAGE_WEBSTORAGEAREA_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 18 matching lines @@
   unsigned length() override;
   blink::WebString key(unsigned index) override;
   blink::WebString getItem(const blink::WebString& key) override;
   void setItem(const blink::WebString& key,
                const blink::WebString& value,
                const blink::WebURL& page_url,
                WebStorageArea::Result& result) override;
   void removeItem(const blink::WebString& key,
                   const blink::WebURL& page_url) override;
   void clear(const blink::WebURL& url) override;
-  size_t memoryBytesUsedByCache() const override;
 
  private:
   int connection_id_;
   scoped_refptr<DOMStorageCachedArea> cached_area_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_DOM_STORAGE_WEBSTORAGEAREA_IMPL_H_