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

ios/chrome/browser/ui/alert_coordinator/alert_coordinator_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>
 
-#import "base/mac/scoped_nsobject.h"
 #include "components/strings/grit/components_strings.h"
 #import "ios/chrome/browser/ui/alert_coordinator/alert_coordinator.h"
 #import "ios/chrome/test/earl_grey/chrome_matchers.h"
 #import "ios/chrome/test/earl_grey/chrome_test_case.h"
 #import "ios/testing/earl_grey/disabled_test_macros.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 NSString* kTitle = @"Foo Title";
 }  // namespace
 
 // Integration test for the alert coordinator using Earl Grey.
 @interface AlertCoordinatorTestCase : ChromeTestCase
 
 // Whether an alert is presented.
 - (BOOL)isPresentingAlert;
 
 @end
 
 @implementation AlertCoordinatorTestCase
 
 // Tests that if the alert coordinator is destroyed, the alert is dismissed.
 - (void)testDismissOnDestroy {
 // TODO(crbug.com/663026): Reenable the test for devices.
 #if !TARGET_IPHONE_SIMULATOR
   EARL_GREY_TEST_DISABLED(@"Disabled for devices because existing system "
                           @"alerts would prevent app alerts to present "
                           @"correctly.");
 #endif
 
   UIViewController* topViewController =
       [[[UIApplication sharedApplication] keyWindow] rootViewController];
 
-  base::scoped_nsobject<AlertCoordinator> alertCoordinator(
+  AlertCoordinator* alertCoordinator =
       [[AlertCoordinator alloc] initWithBaseViewController:topViewController
                                                      title:kTitle
-                                                   message:nil]);
+                                                   message:nil];
 
   [alertCoordinator start];
 
   GREYAssertTrue([self isPresentingAlert], @"An alert should be presented");
 
-  alertCoordinator.reset();
+  alertCoordinator = nil;

[gambard, 2017/02/08 16:08:29]

The alert coordinator needs to be dealloc here, before the next instruction. Is
this guaranteed with ARC?

[stkhapugin, 2017/02/08 17:39:29]

Generally, it is incorrect to assume exact object lifetimes both under ARC and
without ARC for Objective-C reference counted objects. 

[gambard, 2017/02/09 09:06:45]

Acknowledged.

 
   GREYAssertFalse([self isPresentingAlert], @"The alert should be removed");
 }
 
 - (void)testNoInteractionActionAfterTap {
 // TODO(crbug.com/663026): Reenable the test for devices.
 #if !TARGET_IPHONE_SIMULATOR
   EARL_GREY_TEST_DISABLED(@"Disabled for devices because existing system "
                           @"alerts would prevent app alerts to present "
                           @"correctly.");
 #endif
 
   UIViewController* topViewController =
       [[[UIApplication sharedApplication] keyWindow] rootViewController];
 
-  base::scoped_nsobject<AlertCoordinator> alertCoordinator(
+  AlertCoordinator* alertCoordinator =
       [[AlertCoordinator alloc] initWithBaseViewController:topViewController
                                                      title:kTitle
-                                                   message:nil]);
+                                                   message:nil];
 
   __block BOOL blockCalled = NO;
 
   [alertCoordinator setNoInteractionAction:^{
     blockCalled = YES;
   }];
 
   [alertCoordinator start];
 
   GREYAssertTrue([self isPresentingAlert], @"An alert should be presented");
@@ skipping 11 matching lines @@
 - (BOOL)isPresentingAlert {
   NSError* error = nil;
   [[EarlGrey selectElementWithMatcher:grey_accessibilityLabel(kTitle)]
       assertWithMatcher:grey_sufficientlyVisible()
                   error:&error];
 
   return (error == nil);
 }
 
 @end