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

ios/chrome/browser/net/cookies_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.
 
 #include <map>
 #include <memory>
 #include <string>
 
 #import <EarlGrey/EarlGrey.h>
 #import <XCTest/XCTest.h>
 
 #include "base/mac/foundation_util.h"
 #include "base/strings/sys_string_conversions.h"
 #import "ios/chrome/test/app/chrome_test_util.h"
 #import "ios/chrome/test/app/tab_test_util.h"
 #import "ios/chrome/test/earl_grey/chrome_earl_grey.h"
 #import "ios/chrome/test/earl_grey/chrome_test_case.h"
 #include "ios/web/public/test/http_server.h"
 #include "ios/web/public/test/http_server_util.h"
 #include "ios/web/public/test/response_providers/html_response_provider.h"
 #include "ios/web/public/test/response_providers/response_provider.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 const char kTestUrlNormalBrowsing[] = "http://choux/normal/browsing";
 const char kTestUrlNormalSetCookie[] = "http://choux/normal/set_cookie";
 const char kTestUrlIncognitoBrowsing[] = "http://choux/incognito/browsing";
 const char kTestUrlIncognitoSetCookie[] = "http://choux/incognito/set_cookie";
 
 const char kTestResponse[] = "fleur";
 NSString* const kNormalCookieName = @"request";
 NSString* const kNormalCookieValue = @"pony";
@@ skipping 42 matching lines @@
   [ChromeEarlGrey
       loadURL:web::test::HttpServer::MakeUrl(kTestUrlNormalBrowsing)];
   NSString* const clearCookieScript =
       @"var cookies = document.cookie.split(';');"
        "for (var i = 0; i < cookies.length; i++) {"
        "  var cookie = cookies[i];"
        "  var eqPos = cookie.indexOf('=');"
        "  var name = eqPos > -1 ? cookie.substr(0, eqPos) : cookie;"
        "  document.cookie = name + '=;expires=Thu, 01 Jan 1970 00:00:00 GMT';"
        "}";
-  NSError* error = nil;
+  __unsafe_unretained NSError* error = nil;
   chrome_test_util::ExecuteJavaScript(clearCookieScript, &error);
   [super tearDown];
 }
 
 #pragma mark - Tests
 
 // Tests toggling between Normal tabs and Incognito tabs. Different cookies
 // (request=pony for normal tabs, secret=rainbow for incognito tabs) are set.
 // The goal is to verify that cookies set in incognito tabs are available in
 // incognito tabs but not available in normal tabs. Cookies set in incognito
@@ skipping 172 matching lines @@
       loadURL:web::test::HttpServer::MakeUrl(kTestUrlNormalBrowsing)];
   cookies = [ChromeEarlGrey cookies];
   GREYAssertEqualObjects(
       kNormalCookieValue, cookies[kNormalCookieName],
       @"Normal cookie should still be found in normal mode.");
   GREYAssertEqual(1U, cookies.count,
                   @"Only one cookie should be found in normal mode.");
 }
 
 @end