service worker: Implement NavigationPreloadManager.setHeaderValue

content/common/service_worker/service_worker_types.h

Index: content/common/service_worker/service_worker_types.h
diff --git a/content/common/service_worker/service_worker_types.h b/content/common/service_worker/service_worker_types.h
index 4dbe26f8e7ee0b13233ba9d247099be503017a66..589a6a40fd0a05fd8f13907a354d42cd7a23dd58 100644
--- a/content/common/service_worker/service_worker_types.h
+++ b/content/common/service_worker/service_worker_types.h
@@ -272,6 +272,14 @@ struct ExtendableMessageEventSource {
   ServiceWorkerObjectInfo service_worker_info;
 };
 
+struct CONTENT_EXPORT NavigationPreloadState {
+  NavigationPreloadState();
+  NavigationPreloadState(bool enabled, std::string header);
+  NavigationPreloadState(const NavigationPreloadState& other);
+  bool enabled;
+  std::string header;
+};
+
 }  // namespace content
 
 #endif  // CONTENT_COMMON_SERVICE_WORKER_SERVICE_WORKER_TYPES_H_