Load offline page if reading list entry takes more than 1s to load.

ios/chrome/browser/reading_list/reading_list_model_impl.h

Index: ios/chrome/browser/reading_list/reading_list_model_impl.h
diff --git a/ios/chrome/browser/reading_list/reading_list_model_impl.h b/ios/chrome/browser/reading_list/reading_list_model_impl.h
index d185c5193618190144f0d2e3de6541d1e11aaa52..28debf78ca77312036b7a6f7bf7ff35007c627e6 100644
--- a/ios/chrome/browser/reading_list/reading_list_model_impl.h
+++ b/ios/chrome/browser/reading_list/reading_list_model_impl.h
@@ -25,8 +25,11 @@ class ReadingListModelImpl : public ReadingListModel, public KeyedService {
   ReadingListModelImpl();
 
   ~ReadingListModelImpl() override;
+
+  // KeyedService implementation.
   void Shutdown() override;
 
+  // ReadingListModel implementation.
   bool loaded() const override;
 
   size_t unread_size() const override;
@@ -35,9 +38,9 @@ class ReadingListModelImpl : public ReadingListModel, public KeyedService {
   bool HasUnseenEntries() const override;
   void ResetUnseenEntries() override;
 
-  // Returns a specific entry.
-  const ReadingListEntry& GetUnreadEntryAtIndex(size_t index) const override;
-  const ReadingListEntry& GetReadEntryAtIndex(size_t index) const override;
+  const ReadingListEntry* GetUnreadEntryAtIndex(size_t index) const override;
+  const ReadingListEntry* GetReadEntryAtIndex(size_t index) const override;
+  const ReadingListEntry* GetEntryFromURL(const GURL& gurl) const override;
 
   bool CallbackEntryURL(
       const GURL& url,