Implement EmbeddedWorkerContextClient.setCachedMetadata/clearCachedMetadata

content/browser/service_worker/service_worker_disk_cache.h

Index: content/browser/service_worker/service_worker_disk_cache.h
diff --git a/content/browser/service_worker/service_worker_disk_cache.h b/content/browser/service_worker/service_worker_disk_cache.h
index 7fa51eed6348d5850143d9342d02e942a6d0e06d..7b9b4e441933f076c1f395e5bf4812dddcfbf0fd 100644
--- a/content/browser/service_worker/service_worker_disk_cache.h
+++ b/content/browser/service_worker/service_worker_disk_cache.h
@@ -40,6 +40,15 @@ class CONTENT_EXPORT ServiceWorkerResponseWriter
       ServiceWorkerDiskCache* disk_cache);
 };
 
+class CONTENT_EXPORT ServiceWorkerResponseMetadataWriter
+    : public AppCacheResponseMetadataWriter {
+ protected:
+  // Should only be constructed by the storage class.
+  friend class ServiceWorkerStorage;
+  ServiceWorkerResponseMetadataWriter(int64 response_id,
+                                      ServiceWorkerDiskCache* disk_cache);
+};
+
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DISK_CACHE_H_