[Offline] Adding archiver interface

components/offline_pages/offline_page_archiver.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/offline_pages/offline_page_archiver.h"
+
+
+namespace offline_pages {
+
+OfflinePageArchiver::Request::Request(const GURL& url)
+    : url(url){
+}
+
+OfflinePageArchiver::Request::~Request() {
+}
+
+OfflinePageArchiver::Client::Client() {
+}
+
+OfflinePageArchiver::Client::~Client() {
+}
+
+OfflinePageArchiver::OfflinePageArchiver() {
+}
+
+OfflinePageArchiver::~OfflinePageArchiver() {
+}
+
+}  // namespace offline_pages