[BlobAsync] Disk support for blob storage

storage/browser/blob/blob_data_item.h

Index: storage/browser/blob/blob_data_item.h
diff --git a/storage/browser/blob/blob_data_item.h b/storage/browser/blob/blob_data_item.h
index a711a4caf3b3fe4bc969be9e63c87bb33aa79834..f788e7050f4765aae25989e6339c09870d6fc7de 100644
--- a/storage/browser/blob/blob_data_item.h
+++ b/storage/browser/blob/blob_data_item.h
@@ -63,9 +63,13 @@ class STORAGE_EXPORT BlobDataItem : public base::RefCounted<BlobDataItem> {
     return disk_cache_side_stream_index_;
   }
 
+  const scoped_refptr<DataHandle>& data_handle() const { return data_handle_; }
+
  private:
   friend class BlobDataBuilder;
+  friend class BlobMemoryController;
   friend class BlobStorageContext;
+  friend struct BlobSlice;
   friend class base::RefCounted<BlobDataItem>;
   friend STORAGE_EXPORT void PrintTo(const BlobDataItem& x, ::std::ostream* os);