Remove void** from disk_cache interface.

net/url_request/view_cache_helper.h

Index: net/url_request/view_cache_helper.h
diff --git a/net/url_request/view_cache_helper.h b/net/url_request/view_cache_helper.h
index d5a7c423d68df01347e6c0feea9da3069f29d0d0..c1de152b14d9c40001a21437d1167f00e62ac817 100644
--- a/net/url_request/view_cache_helper.h
+++ b/net/url_request/view_cache_helper.h
@@ -11,11 +11,7 @@
 #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 {
 
@@ -102,7 +98,7 @@ class NET_EXPORT ViewCacheHelper {
   const URLRequestContext* context_;
   disk_cache::Backend* disk_cache_;
   disk_cache::Entry* entry_;
-  void* iter_;
+  disk_cache::Backend::Iterator iter_;
   scoped_refptr<IOBuffer> buf_;
   int buf_len_;
   int index_;