[ObjC ARC] Converts ios/chrome/browser/ui/dialogs:unit_tests_internal to ARC.

ios/chrome/browser/ui/dialogs/dialog_presenter_unittest.mm

 // Copyright 2015 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 "ios/chrome/browser/ui/dialogs/dialog_presenter.h"
 
-#import "base/mac/scoped_nsobject.h"
 #include "base/time/time.h"
 #import "ios/chrome/browser/ui/alert_coordinator/alert_coordinator.h"
 #import "ios/web/public/test/fakes/test_web_state.h"
 #include "ios/web/public/web_state/web_state_observer.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 // TestWebState subclass that supports the WebStateDestroyed() callback for a
 // single observer.
 class DialogPresenterTestWebState : public web::TestWebState {
  public:
   DialogPresenterTestWebState() : web::TestWebState(), observer_(nullptr) {}
   ~DialogPresenterTestWebState() override {
     if (observer_)
       observer_->WebStateDestroyed();
   }
@@ skipping 43 matching lines @@
   }
   ~DialogPresenterTest() override {
     [[presenter_ presentedDialogCoordinator] stop];
   }
 
   TestDialogPresenterDelegate* delegate() { return delegate_; }
   UIViewController* viewController() { return viewController_; }
   DialogPresenter* presenter() { return presenter_; }
 
  private:
-  base::scoped_nsobject<TestDialogPresenterDelegate> delegate_;
-  base::scoped_nsobject<UIViewController> viewController_;
-  base::scoped_nsobject<DialogPresenter> presenter_;
+  TestDialogPresenterDelegate* delegate_;
+  UIViewController* viewController_;
+  DialogPresenter* presenter_;
 };
 
 // Tests that a dialog was successfully shown and that the delegate was notified
 // with the correct context.
 TEST_F(DialogPresenterTest, SimpleTest) {
   DialogPresenterTestWebState webState;
   [presenter() runJavaScriptAlertPanelWithMessage:@""
                                        requestURL:GURL()
                                          webState:&webState
                                 completionHandler:nil];
@@ skipping 109 matching lines @@
                                   completion3_called = YES;
                                 }];
   EXPECT_EQ(1U, delegate().presentedWebStates.size());
   EXPECT_EQ(&webState1, delegate().presentedWebStates.front());
   // Cancel all dialogs and verify that all |completion_called| were called.
   [presenter() cancelAllDialogs];
   EXPECT_TRUE(completion1_called);
   EXPECT_TRUE(completion2_called);
   EXPECT_TRUE(completion3_called);
 }