Have the RequestCoordinator generate the offline_id

chrome/browser/android/offline_pages/recent_tab_helper.cc

 // Copyright (c) 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/recent_tab_helper.h"
 
 #include <queue>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 148 matching lines @@
     // If previous pages can't be deleted, don't add new ones.
     ReportSnapshotCompleted();
     return;
   }
 
   if (!IsSamePage()) {
     ReportSnapshotCompleted();
     return;
   }
 
-  page_model_->SavePage(
-      snapshot_url_, client_id(),
-      delegate_->CreatePageArchiver(web_contents()),
-      base::Bind(&RecentTabHelper::SavePageCallback,
-                 weak_ptr_factory_.GetWeakPtr()));
+  page_model_->SavePage(snapshot_url_, client_id(), 0ul,

[dougarnett, 2016/08/18 17:59:07]

possibly dumb C++ question: why are you using "u" when the type seems to be
signed (int64_t)?

+                        delegate_->CreatePageArchiver(web_contents()),
+                        base::Bind(&RecentTabHelper::SavePageCallback,
+                                   weak_ptr_factory_.GetWeakPtr()));
 }
 
 void RecentTabHelper::SavePageCallback(OfflinePageModel::SavePageResult result,
                                        int64_t offline_id) {
   ReportSnapshotCompleted();
 }
 
 void RecentTabHelper::ReportSnapshotCompleted() {
   snapshot_controller_->PendingSnapshotCompleted();
 }
 
 bool RecentTabHelper::IsSamePage() const {
   return web_contents() &&
          (web_contents()->GetLastCommittedURL() == snapshot_url_);
 }
 
 ClientId RecentTabHelper::client_id() const {
   return ClientId(kLastNNamespace, tab_id_);
 }
 
 }  // namespace offline_pages