Have the RequestCoordinator generate the offline_id

chrome/browser/android/offline_pages/downloads/offline_page_download_bridge.cc

 // Copyright 2016 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 "chrome/browser/android/offline_pages/downloads/offline_page_download_bridge.h"
 
 #include <vector>
 
 #include "base/android/jni_string.h"
 #include "base/guid.h"
@@ skipping 130 matching lines @@
 
   GURL url = web_contents->GetLastCommittedURL();
   auto archiver =
       base::MakeUnique<offline_pages::OfflinePageMHTMLArchiver>(web_contents);
 
   offline_pages::ClientId client_id;
   client_id.name_space = offline_pages::kDownloadNamespace;
   client_id.id = base::GenerateGUID();
 
   offline_page_model->SavePage(
-      url, client_id, std::move(archiver),
+      url, client_id, 0ul, std::move(archiver),
       base::Bind(&OfflinePageDownloadBridge::SavePageCallback,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
 void OfflinePageDownloadBridge::ItemsLoaded() {
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> obj = weak_java_ref_.get(env);
   if (obj.is_null())
     return;
   Java_OfflinePageDownloadBridge_downloadItemsLoaded(env, obj.obj());
@@ skipping 40 matching lines @@
 
   DownloadUIAdapter* adapter =
       DownloadUIAdapter::FromOfflinePageModel(offline_page_model);
 
   return reinterpret_cast<jlong>(
       new OfflinePageDownloadBridge(env, obj, adapter));
 }
 
 }  // namespace android
 }  // namespace offline_pages