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

ios/chrome/browser/reading_list/reading_list_download_service.cc

Index: ios/chrome/browser/reading_list/reading_list_download_service.cc
diff --git a/ios/chrome/browser/reading_list/reading_list_download_service.cc b/ios/chrome/browser/reading_list/reading_list_download_service.cc
index c6a2a0bb8ecd6188e6f3bc84c3991ae6cc354ad4..d686472f5dbf3cc0166e494ad3c51121067c7e41 100644
--- a/ios/chrome/browser/reading_list/reading_list_download_service.cc
+++ b/ios/chrome/browser/reading_list/reading_list_download_service.cc
@@ -62,14 +62,18 @@ void ReadingListDownloadService::ReadingListWillRemoveReadEntry(
     const ReadingListModel* model,
     size_t index) {
   DCHECK_EQ(reading_list_model_, model);
-  RemoveDownloadedEntry(model->GetReadEntryAtIndex(index));
+  const ReadingListEntry* entry = model->GetReadEntryAtIndex(index);
+  if (entry)
+    RemoveDownloadedEntry(*entry);
 }
 
 void ReadingListDownloadService::ReadingListWillRemoveUnreadEntry(
     const ReadingListModel* model,
     size_t index) {
   DCHECK_EQ(reading_list_model_, model);
-  RemoveDownloadedEntry(model->GetUnreadEntryAtIndex(index));
+  const ReadingListEntry* entry = model->GetUnreadEntryAtIndex(index);
+  if (entry)
+    RemoveDownloadedEntry(*entry);
 }
 
 void ReadingListDownloadService::ReadingListWillAddUnreadEntry(
@@ -90,14 +94,16 @@ void ReadingListDownloadService::DownloadAllEntries() {
   DCHECK(reading_list_model_->loaded());
   size_t size = reading_list_model_->unread_size();
   for (size_t i = 0; i < size; i++) {
-    const ReadingListEntry& entry =
+    const ReadingListEntry* entry =
         reading_list_model_->GetUnreadEntryAtIndex(i);
-    this->ScheduleDownloadEntry(entry);
+    if (entry)
+      this->ScheduleDownloadEntry(*entry);
   }
   size = reading_list_model_->read_size();
   for (size_t i = 0; i < size; i++) {
-    const ReadingListEntry& entry = reading_list_model_->GetReadEntryAtIndex(i);
-    this->ScheduleDownloadEntry(entry);
+    const ReadingListEntry* entry = reading_list_model_->GetReadEntryAtIndex(i);
+    if (entry)
+      this->ScheduleDownloadEntry(*entry);
   }
 }