Use shared matchers for common elements.

ios/chrome/browser/ui/ntp/new_tab_page_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 <XCTest/XCTest.h>
 
 #include "components/strings/grit/components_strings.h"
 #import "ios/chrome/browser/ui/commands/generic_chrome_command.h"
 #include "ios/chrome/browser/ui/commands/ios_command_ids.h"
@@ skipping 270 matching lines @@
         assertWithMatcher:grey_notVisible()];
   }
 }
 
 // Tests that the NTP's toolbar is not visible when the NTP is scrolled up.
 - (void)testScrollToolbar {
   if (IsIPadIdiom()) {
     EARL_GREY_TEST_SKIPPED(@"Skipped for iPad (no hidden toolbar in tablet)");
   }
 
-  NSString* tabSwitcherLabel =
-      l10n_util::GetNSString(IDS_IOS_TOOLBAR_SHOW_TABS);
   NSString* toolsMenuLabel = l10n_util::GetNSString(IDS_IOS_TOOLBAR_SETTINGS);
 
   // Check that the toolbar's tab switcher and tools menu buttons are visible.
-  [[EarlGrey selectElementWithMatcher:grey_accessibilityLabel(tabSwitcherLabel)]
+  [[EarlGrey selectElementWithMatcher:chrome_test_util::ShowTabsButton()]
       assertWithMatcher:grey_sufficientlyVisible()];
   [[EarlGrey selectElementWithMatcher:grey_accessibilityLabel(toolsMenuLabel)]
       assertWithMatcher:grey_sufficientlyVisible()];
   AssertNTPScrolledToTop(NO);
 
   // Swipe up the NTP. The omnibox should be fixed at the top of the screen.
   id<GREYMatcher> matcher = grey_accessibilityID(@"Google Landing");
   [[EarlGrey selectElementWithMatcher:matcher]
       performAction:grey_swipeFastInDirection(kGREYDirectionUp)];
   AssertNTPScrolledToTop(YES);
 
   // Check that tab switcher and tools menu buttons are not on screen.
-  [[EarlGrey selectElementWithMatcher:grey_accessibilityLabel(tabSwitcherLabel)]
+  [[EarlGrey selectElementWithMatcher:chrome_test_util::ShowTabsButton()]
       assertWithMatcher:grey_notVisible()];
   [[EarlGrey selectElementWithMatcher:grey_accessibilityLabel(toolsMenuLabel)]
       assertWithMatcher:grey_notVisible()];
 }
 
 @end