Gallery.app : shows an error message when it fails to save an image.

ui/file_manager/gallery/js/gallery_item.js

Index: ui/file_manager/gallery/js/gallery_item.js
diff --git a/ui/file_manager/gallery/js/gallery_item.js b/ui/file_manager/gallery/js/gallery_item.js
index 565067495ac31a8ed361654e43c21ad04aefe3a6..4fe4bf5995754b46be182bde820b28864925d81c 100644
--- a/ui/file_manager/gallery/js/gallery_item.js
+++ b/ui/file_manager/gallery/js/gallery_item.js
@@ -306,9 +306,11 @@ Gallery.Item.prototype.saveToFile = function(
     }).then(onSuccess.bind(null, fileEntry))
     .catch(function(error) {
       onError(error);
-      // Disable all callbacks on the first error.
-      fileWriter.onerror = null;
-      fileWriter.onwriteend = null;
+      if (fileWriter) {
+        // Disable all callbacks on the first error.
+        fileWriter.onerror = null;
+        fileWriter.onwriteend = null;
+      }
     });
   }.bind(this);