Do not snapshot error pages

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 6081dac07565436e825852c998d5f34d97145ea2..afb1eecc354579f32914e8f9d789d27efe58cdaa 100644
--- a/chrome/browser/android/offline_pages/recent_tab_helper.cc
+++ b/chrome/browser/android/offline_pages/recent_tab_helper.cc
@@ -92,6 +92,12 @@ void RecentTabHelper::StartSnapshot() {
   if (never_do_snapshots_)
     return;
 
+  // Ignores any non-normal pages, like error pages.
+  content::NavigationEntry* entry =
+      web_contents()->GetController().GetLastCommittedEntry();
+  if (!entry || entry->GetPageType() != content::PAGE_TYPE_NORMAL)
+    return;
+
   GURL url = web_contents()->GetLastCommittedURL();
   bool can_save = OfflinePageModel::CanSaveURL(url);
   UMA_HISTOGRAM_BOOLEAN("OfflinePages.CanSaveRecentPage", can_save);