CacheStorage: Implement Cache.addAll() behind a flag

Source/modules/cachestorage/Cache.idl

Index: Source/modules/cachestorage/Cache.idl
diff --git a/Source/modules/cachestorage/Cache.idl b/Source/modules/cachestorage/Cache.idl
index c6074a9be319424f3efa1dc4dfc4fe730168ec10..56e24bf233f8eb53817d7f7b0671e5b23203e1e5 100644
--- a/Source/modules/cachestorage/Cache.idl
+++ b/Source/modules/cachestorage/Cache.idl
@@ -17,10 +17,7 @@
     // [CallWith=ScriptState, RaisesException] Promise<sequence<Response>> matchAll(RequestInfo request, optional CacheQueryOptions options);
 
     [CallWith=ScriptState, RaisesException] Promise<void> add(RequestInfo request);
-
-    // FIXME: Implement addAll(): http://crbug.com/427652
-    // [CallWith=ScriptState] Promise<void> addAll(sequence<RequestInfo> requests);
-
+    [CallWith=ScriptState, RaisesException] Promise<void> addAll(sequence<RequestInfo> requests);
     [CallWith=ScriptState, RaisesException] Promise<void> put(RequestInfo request, Response response);
     [CallWith=ScriptState, ImplementedAs=deleteFunction, RaisesException] Promise<boolean> delete(RequestInfo request, optional CacheQueryOptions options);
     [CallWith=ScriptState, RaisesException] Promise<sequence<Response>> keys(optional RequestInfo request, optional CacheQueryOptions options);