[ObjC ARC] Converts ios/chrome/browser/ui/tab_switcher:eg_tests to ARC.

ios/chrome/browser/ui/tab_switcher/tab_switcher_controller_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/mac/scoped_nsobject.h"
 #include "base/test/scoped_command_line.h"
 #import "ios/chrome/app/main_controller_private.h"
 #include "ios/chrome/browser/chrome_switches.h"
 #import "ios/chrome/browser/ui/commands/generic_chrome_command.h"
 #include "ios/chrome/browser/ui/commands/ios_command_ids.h"
 #import "ios/chrome/browser/ui/tools_menu/tools_menu_view_controller.h"
 #import "ios/chrome/browser/ui/ui_util.h"
 #include "ios/chrome/grit/ios_strings.h"
 #import "ios/chrome/test/app/chrome_test_util.h"
 #import "ios/chrome/test/earl_grey/chrome_earl_grey_ui.h"
 #import "ios/chrome/test/earl_grey/chrome_matchers.h"
 #import "ios/chrome/test/earl_grey/chrome_test_case.h"
 #include "ui/base/l10n/l10n_util.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 using chrome_test_util::ButtonWithAccessibilityLabel;
 using chrome_test_util::ButtonWithAccessibilityLabelId;
 using chrome_test_util::StaticTextWithAccessibilityLabelId;
 
 namespace {
 
 // Returns the GREYMatcher for the button that closes the tab switcher.
 id<GREYMatcher> TabSwitcherCloseButton() {
   return ButtonWithAccessibilityLabelId(IDS_IOS_TAB_STRIP_LEAVE_TAB_SWITCHER);
 }
@@ skipping 32 matching lines @@
   [ChromeEarlGreyUI openToolsMenu];
   id<GREYMatcher> newIncognitoTabButtonMatcher =
       grey_accessibilityID(kToolsMenuNewIncognitoTabId);
   [[EarlGrey selectElementWithMatcher:newIncognitoTabButtonMatcher]
       performAction:grey_tap()];
 }
 
 // Triggers the opening of the tab switcher by launching a command. Should be
 // called only when the tab switcher is not presented.
 void EnterTabSwitcherWithCommand() {
-  base::scoped_nsobject<GenericChromeCommand> command(
-      [[GenericChromeCommand alloc] initWithTag:IDC_TOGGLE_TAB_SWITCHER]);
+  GenericChromeCommand* command =
+      [[GenericChromeCommand alloc] initWithTag:IDC_TOGGLE_TAB_SWITCHER];
   chrome_test_util::RunCommandWithActiveViewController(command);
 }
 
 }  // namespace
 
 @interface TabSwitcherControllerTestCase : ChromeTestCase
 @end
 
 @implementation TabSwitcherControllerTestCase {
   std::unique_ptr<base::test::ScopedCommandLine> scoped_command_line_;
@@ skipping 124 matching lines @@
 
   // Press the :: icon to exit the tab switcher.
   [[EarlGrey selectElementWithMatcher:TabSwitcherCloseButton()]
       performAction:grey_tap()];
 
   // Verify that we've left the tab switcher.
   [self assertTabSwitcherIsInactive];
 }
 
 @end