Remove void** from disk_cache interface.

net/disk_cache/blockfile/backend_impl_v3.cc

Index: net/disk_cache/blockfile/backend_impl_v3.cc
diff --git a/net/disk_cache/blockfile/backend_impl_v3.cc b/net/disk_cache/blockfile/backend_impl_v3.cc
index e5c6033ebb99086ed41d30e283e0e912aac4fce0..58a0ff8b7a7e52ffea95ffd449e27c67f451b471 100644
--- a/net/disk_cache/blockfile/backend_impl_v3.cc
+++ b/net/disk_cache/blockfile/backend_impl_v3.cc
@@ -668,10 +668,32 @@ int BackendImplV3::DoomEntriesSince(base::Time initial_time,
   }
 }
 
-int BackendImplV3::OpenNextEntry(void** iter, Entry** next_entry,
+int BackendImplV3::OpenNextEntry(Iterator* iter, Entry** next_entry,
                                  const CompletionCallback& callback) {
+  // TODO(gavinp): Remove all void** iter from cache.
   DCHECK(!callback.is_null());
-  background_queue_.OpenNextEntry(iter, next_entry, callback);
+  class State : public EnumerationState {
+   public:
+    State(base::WeakPtr<InFlightBackendIO> background_queue)
+        : background_queue_(background_queue),
+          iter_(NULL) {}
+
+    virtual ~State() {
+      if (background_queue_)
+        background_queue_->EndEnumeration(*iter());
+    }
+
+    void** iter() { return &iter_; }
+
+   private:
+    base::WeakPtr<InFlightBackendIO> background_queue_;
+    void* iter_;
+  };
+  if (!*iter)
+    iter->reset(new State(GetBackgroundQueue()));
+  State* state = static_cast<State*>(iter->get());
+
+  background_queue_.OpenNextEntry(state->iter(), next_entry, callback);
   return net::ERR_IO_PENDING;
 }
 
@@ -1585,15 +1607,11 @@ int BackendImplV3::DoomEntriesSince(base::Time initial_time,
   return net::ERR_FAILED;
 }
 
-int BackendImplV3::OpenNextEntry(void** iter, Entry** next_entry,
+int BackendImplV3::OpenNextEntry(Iterator* iter, Entry** next_entry,
                                  const CompletionCallback& callback) {
   return net::ERR_FAILED;
 }
 
-void BackendImplV3::EndEnumeration(void** iter) {
-  NOTIMPLEMENTED();
-}
-
 void BackendImplV3::GetStats(StatsItems* stats) {
   NOTIMPLEMENTED();
 }