Break deserializer reservations into chunks that fit onto a page.

src/list.h

Index: src/list.h
diff --git a/src/list.h b/src/list.h
index ea5fd1e0cac37a0840a7e3f1eb4dea8f6acdff53..c17c4ecfee580805fbdb4ae2d2744c409cf32318 100644
--- a/src/list.h
+++ b/src/list.h
@@ -80,7 +80,9 @@ class List {
 
   Vector<T> ToVector() const { return Vector<T>(data_, length_); }
 
-  Vector<const T> ToConstVector() { return Vector<const T>(data_, length_); }
+  Vector<const T> ToConstVector() const {
+    return Vector<const T>(data_, length_);
+  }
 
   // Adds a copy of the given 'element' to the end of the list,
   // expanding the list if necessary.