Make the condition for when this is predeclared easier to understand.

src/ast/scopes.h

Index: src/ast/scopes.h
diff --git a/src/ast/scopes.h b/src/ast/scopes.h
index f93c6fa1929a84c386caf09d5b8fc59863c2faf0..eacda64cc5f110dc7765582b67e1b06d512ff023 100644
--- a/src/ast/scopes.h
+++ b/src/ast/scopes.h
@@ -587,7 +587,7 @@ class DeclarationScope : public Scope {
   DeclarationScope(Zone* zone, ScopeType scope_type,
                    Handle<ScopeInfo> scope_info);
   // Creates a script scope.
-  explicit DeclarationScope(Zone* zone);
+  DeclarationScope(Zone* zone, AstValueFactory* ast_value_factory);
 
   bool IsDeclaredParameter(const AstRawString* name) {
     // If IsSimpleParameterList is false, duplicate parameters are not allowed,