Add tests against pressing tab when a view controller is presented

ios/chrome/browser/ui/reading_list/reading_list_egtest.mm

Index: ios/chrome/browser/ui/reading_list/reading_list_egtest.mm
diff --git a/ios/chrome/browser/ui/reading_list/reading_list_egtest.mm b/ios/chrome/browser/ui/reading_list/reading_list_egtest.mm
index 09dcb12934243649a1d594430383915246fa69b5..6d16b55b4fac809add3074c22bb5ad1e8f885383 100644
--- a/ios/chrome/browser/ui/reading_list/reading_list_egtest.mm
+++ b/ios/chrome/browser/ui/reading_list/reading_list_egtest.mm
@@ -445,4 +445,10 @@ size_t ModelReadSize(ReadingListModel* model) {
                  GetReadingListModel()->unread_size());
 }
 
+// Tests that hitting the tab key doesn't trigger the omnibox in the background.
+// Testing against regressions of the fix for crbug.com/676993.
+- (void)testTabKeyIsANoOp {
+  TODO
+}
+
 @end