Reland of "Remove void** from disk_cache interface" w/ blockfile iter fix.

net/url_request/view_cache_helper.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 NET_URL_REQUEST_VIEW_CACHE_HELPER_H_
 #define NET_URL_REQUEST_VIEW_CACHE_HELPER_H_
 
 #include <string>
 
 #include "base/memory/weak_ptr.h"
 #include "net/base/completion_callback.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_export.h"
-
-namespace disk_cache {
-class Backend;
-class Entry;
-}  // namespace disk_cache
+#include "net/disk_cache/disk_cache.h"
 
 namespace net {
 
 class URLRequestContext;
 
 class NET_EXPORT ViewCacheHelper {
  public:
   ViewCacheHelper();
   ~ViewCacheHelper();
 
@@ skipping 66 matching lines @@
   int DoReadResponseComplete(int result);
   int DoReadData();
   int DoReadDataComplete(int result);
 
   // Called to signal completion of asynchronous IO.
   void OnIOComplete(int result);
 
   const URLRequestContext* context_;
   disk_cache::Backend* disk_cache_;
   disk_cache::Entry* entry_;
-  void* iter_;
+  scoped_ptr<disk_cache::Backend::Iterator> iter_;
   scoped_refptr<IOBuffer> buf_;
   int buf_len_;
   int index_;
 
   std::string key_;
   std::string url_prefix_;
   std::string* data_;
   CompletionCallback callback_;
 
   State next_state_;
 
   base::WeakPtrFactory<ViewCacheHelper> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewCacheHelper);
 };
 
 }  // namespace net.
 
 #endif  // NET_URL_REQUEST_VIEW_CACHE_HELPER_H_