diff --git a/tools/gn/bundle_file_rule.cc b/tools/gn/bundle_file_rule.cc
index 0f42c8f..7684196 100644
--- a/tools/gn/bundle_file_rule.cc
+++ b/tools/gn/bundle_file_rule.cc
@@ -14,6 +14,8 @@
                                const SubstitutionPattern& pattern)
     : sources_(sources), pattern_(pattern) {}
 
+BundleFileRule::BundleFileRule(const BundleFileRule& other) = default;
+
 BundleFileRule::~BundleFileRule() {}
 
 SourceFile BundleFileRule::ApplyPatternToSource(
diff --git a/tools/gn/bundle_file_rule.h b/tools/gn/bundle_file_rule.h
index 3669cd2..9fbf012 100644
--- a/tools/gn/bundle_file_rule.h
+++ b/tools/gn/bundle_file_rule.h
@@ -20,6 +20,7 @@
  public:
   BundleFileRule(const std::vector<SourceFile> sources,
                  const SubstitutionPattern& pattern);
+  BundleFileRule(const BundleFileRule& other);
   ~BundleFileRule();
 
   // Applies the substitution pattern to a source file, returning the result