diff --git a/AK/MemoryStream.cpp b/AK/MemoryStream.cpp
index 880d8027c97..47ef8f0f283 100644
--- a/AK/MemoryStream.cpp
+++ b/AK/MemoryStream.cpp
@@ -12,8 +12,9 @@
 
 namespace AK {
 
-FixedMemoryStream::FixedMemoryStream(Bytes bytes)
+FixedMemoryStream::FixedMemoryStream(Bytes bytes, bool writing_enabled)
     : m_bytes(bytes)
+    , m_writing_enabled(writing_enabled)
 {
 }
 
diff --git a/AK/MemoryStream.h b/AK/MemoryStream.h
index ddc4b2ab436..4211bc0284e 100644
--- a/AK/MemoryStream.h
+++ b/AK/MemoryStream.h
@@ -16,7 +16,7 @@ namespace AK {
 /// using a single read/write head.
 class FixedMemoryStream : public SeekableStream {
 public:
-    explicit FixedMemoryStream(Bytes bytes);
+    explicit FixedMemoryStream(Bytes bytes, bool writing_enabled = true);
     explicit FixedMemoryStream(ReadonlyBytes bytes);
 
     virtual bool is_eof() const override;