Remove void** from disk_cache interface.

net/disk_cache/blockfile/backend_impl.cc

Index: net/disk_cache/blockfile/backend_impl.cc
diff --git a/net/disk_cache/blockfile/backend_impl.cc b/net/disk_cache/blockfile/backend_impl.cc
index 0d258351a351bd4a5bddf186e750cac9fc4a324a..fe44bc202740266c8e84dc21c4a054954caa107e 100644
--- a/net/disk_cache/blockfile/backend_impl.cc
+++ b/net/disk_cache/blockfile/backend_impl.cc
@@ -52,6 +52,25 @@ const int kBaseTableLen = 64 * 1024;
 // Avoid trimming the cache for the first 5 minutes (10 timer ticks).
 const int kTrimDelay = 10;
 
+class BackendEnumerationState : public disk_cache::Backend::EnumerationState {
+ public:
+  explicit BackendEnumerationState(
+      base::WeakPtr<disk_cache::InFlightBackendIO> background_queue)
+      : background_queue_(background_queue),
+        data_(NULL) {}
+
+  virtual ~BackendEnumerationState() {
+    if (background_queue_)
+      background_queue_->EndEnumeration(*data());
+  }
+
+  void** data() { return &data_; }
+
+ private:
+  base::WeakPtr<disk_cache::InFlightBackendIO> background_queue_;
+  void* data_;
+};
+
 int DesiredIndexTableLen(int32 storage_size) {
   if (storage_size <= k64kEntriesStore)
     return kBaseTableLen;
@@ -328,10 +347,15 @@ void BackendImpl::CleanupCache() {
 
 // ------------------------------------------------------------------------
 
-int BackendImpl::OpenPrevEntry(void** iter, Entry** prev_entry,
+int BackendImpl::OpenPrevEntry(Iterator* iter, Entry** prev_entry,
                                const CompletionCallback& callback) {
   DCHECK(!callback.is_null());
-  background_queue_.OpenPrevEntry(iter, prev_entry, callback);
+  if (!*iter)
+    iter->reset(new BackendEnumerationState(GetBackgroundQueue()));
+  BackendEnumerationState* state =
+      static_cast<BackendEnumerationState*>(iter->get());
+
+  background_queue_.OpenPrevEntry(state->data(), prev_entry, callback);
   return net::ERR_IO_PENDING;
 }
 
@@ -1199,16 +1223,17 @@ int BackendImpl::DoomEntriesSince(const base::Time initial_time,
   return net::ERR_IO_PENDING;
 }
 
-int BackendImpl::OpenNextEntry(void** iter, Entry** next_entry,
+int BackendImpl::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);
-  return net::ERR_IO_PENDING;
-}
+  if (!*iter)
+    iter->reset(new BackendEnumerationState(GetBackgroundQueue()));
+  BackendEnumerationState* state =
+      static_cast<BackendEnumerationState*>(iter->get());
 
-void BackendImpl::EndEnumeration(void** iter) {
-  background_queue_.EndEnumeration(*iter);
-  *iter = NULL;
+  background_queue_.OpenNextEntry(state->data(), next_entry, callback);
+  return net::ERR_IO_PENDING;
 }
 
 void BackendImpl::GetStats(StatsItems* stats) {