Add tests against pressing tab when a view controller is presented

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <EarlGrey/EarlGrey.h>
 #import <UIKit/UIKit.h>
 #import <XCTest/XCTest.h>
 
 #include "base/strings/sys_string_conversions.h"
 #include "components/reading_list/ios/reading_list_model.h"
@@ skipping 427 matching lines @@
 
   // Tap the action sheet.
   TapButtonWithID(IDS_IOS_READING_LIST_MARK_READ_BUTTON);
 
   AssertAllEntriesVisible();
   XCTAssertEqual(kNumberReadEntries + 1, ModelReadSize(GetReadingListModel()));
   XCTAssertEqual(kNumberUnreadEntries - 1,
                  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