content: Cleanup class/struct forward declarations

content/browser/dom_storage/dom_storage_context_wrapper.h

 // Copyright 2013 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_DOM_STORAGE_DOM_STORAGE_CONTEXT_WRAPPER_H_
 #define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_CONTEXT_WRAPPER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 15 matching lines @@
 class Connector;
 }
 
 namespace storage {
 class SpecialStoragePolicy;
 }
 
 namespace content {
 
 class DOMStorageContextImpl;
-class LevelDBWrapperImpl;
 
 // This is owned by Storage Partition and encapsulates all its dom storage
 // state.
 class CONTENT_EXPORT DOMStorageContextWrapper :
     NON_EXPORTED_BASE(public DOMStorageContext),
     public base::RefCountedThreadSafe<DOMStorageContextWrapper>,
     public base::MemoryCoordinatorClient {
  public:
   // If |data_path| is empty, nothing will be saved to disk.
   DOMStorageContextWrapper(
@@ skipping 57 matching lines @@
   std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
 
   scoped_refptr<DOMStorageContextImpl> context_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(DOMStorageContextWrapper);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_CONTEXT_WRAPPER_H_