Remove unused fields from //content.

content/browser/appcache/appcache_storage_impl.h

Index: content/browser/appcache/appcache_storage_impl.h
diff --git a/content/browser/appcache/appcache_storage_impl.h b/content/browser/appcache/appcache_storage_impl.h
index 113540952f9d3658509d69fb7be54ef057e72e49..1e0963f74508f615ec43e39418a27a0a757ffd97 100644
--- a/content/browser/appcache/appcache_storage_impl.h
+++ b/content/browser/appcache/appcache_storage_impl.h
@@ -64,12 +64,10 @@ class AppCacheStorageImpl : public AppCacheStorage {
                          int response_code) override;
   void StoreEvictionTimes(AppCacheGroup* group) override;
   AppCacheResponseReader* CreateResponseReader(const GURL& manifest_url,
-                                               int64_t group_id,
                                                int64_t response_id) override;
-  AppCacheResponseWriter* CreateResponseWriter(const GURL& manifest_url,
-                                               int64_t group_id) override;
+  AppCacheResponseWriter* CreateResponseWriter(
+      const GURL& manifest_url) override;
   AppCacheResponseMetadataWriter* CreateResponseMetadataWriter(
-      int64_t group_id,
       int64_t response_id) override;
   void DoomResponses(const GURL& manifest_url,
                      const std::vector<int64_t>& response_ids) override;