[Offline Pages] Adds storage for kInvalidOfflineId.

chrome/browser/android/offline_pages/recent_tab_helper.cc

Index: chrome/browser/android/offline_pages/recent_tab_helper.cc
diff --git a/chrome/browser/android/offline_pages/recent_tab_helper.cc b/chrome/browser/android/offline_pages/recent_tab_helper.cc
index 6e75c4abe2788ec2634e90f56537c4759e639c6d..03fd33f48e45598b8a6e5a60bf6c9a5668d82eec 100644
--- a/chrome/browser/android/offline_pages/recent_tab_helper.cc
+++ b/chrome/browser/android/offline_pages/recent_tab_helper.cc
@@ -152,9 +152,8 @@ void RecentTabHelper::DidFinishNavigation(
   }
 
   if (offline_pages::IsOffliningRecentPagesEnabled()) {
-    int64_t proposed_id = OfflinePageModel::kInvalidOfflineId;
     download_info_ = base::MakeUnique<DownloadPageInfo>(
-        GetRecentPagesClientId(), proposed_id);
+        GetRecentPagesClientId(), OfflinePageModel::kInvalidOfflineId);
   } else {
     download_info_.reset();
   }