Disable copy constructor in public: section or use macro.

src/background-parsing-task.h

Index: src/background-parsing-task.h
diff --git a/src/background-parsing-task.h b/src/background-parsing-task.h
index 1bf9d7412127901c7d8706d9fdecf5213cfef372..bd96ee1f857b46f5b736930b8a9d683342f3a998 100644
--- a/src/background-parsing-task.h
+++ b/src/background-parsing-task.h
@@ -39,10 +39,9 @@ struct StreamedSource {
   std::unique_ptr<ParseInfo> info;
   std::unique_ptr<Parser> parser;
 
- private:
-  // Prevent copying. Not implemented.
-  StreamedSource(const StreamedSource&);
-  StreamedSource& operator=(const StreamedSource&);
+  // Prevent copying.
+  StreamedSource(const StreamedSource&) = delete;
+  StreamedSource& operator=(const StreamedSource&) = delete;
 };