[ObjC ARC] Converts ios/web:ios_web_public_unittests to ARC.

ios/web/public/origin_util_unittest.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 "ios/web/public/origin_util.h"
 
 #import <WebKit/WebKit.h>
 
-#import "base/mac/objc_property_releaser.h"
-#import "base/mac/scoped_nsobject.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 // WKSecurityOrigin can not be manually created, hence stub is needed.
 @interface WKSecurityOriginStub : NSObject
 // Methods from WKSecurityOrigin class.
 @property(nonatomic, copy) NSString* protocol;
 @property(nonatomic, copy) NSString* host;
 @property(nonatomic) NSInteger port;
 @end
 
-@implementation WKSecurityOriginStub {
-  base::mac::ObjCPropertyReleaser _propertyReleaser;
-}
+@implementation WKSecurityOriginStub
 @synthesize protocol = _protocol;
 @synthesize host = _host;
 @synthesize port = _port;
-- (instancetype)init {
-  if (self = [super init]) {
-    _propertyReleaser.Init(self, [WKSecurityOriginStub class]);
-  }
-  return self;
-}
 @end
 
 namespace web {
 
 // Tests calling GURLOriginWithWKSecurityOrigin with nil.
 TEST(OriginUtilTest, GURLOriginWithNilWKSecurityOrigin) {
   GURL url(GURLOriginWithWKSecurityOrigin(nil));
 
   EXPECT_FALSE(url.is_valid());
   EXPECT_TRUE(url.spec().empty());
 }
 
 // Tests calling GURLOriginWithWKSecurityOrigin with valid origin.
 TEST(OriginUtilTest, GURLOriginWithValidWKSecurityOrigin) {
-  base::scoped_nsobject<WKSecurityOriginStub> origin(
-      [[WKSecurityOriginStub alloc] init]);
+  WKSecurityOriginStub* origin = [[WKSecurityOriginStub alloc] init];
   [origin setProtocol:@"http"];
   [origin setHost:@"chromium.org"];
   [origin setPort:80];
 
-  GURL url(GURLOriginWithWKSecurityOrigin(
-      static_cast<WKSecurityOrigin*>(origin.get())));
+  GURL url(
+      GURLOriginWithWKSecurityOrigin(static_cast<WKSecurityOrigin*>(origin)));
   EXPECT_EQ("http://chromium.org/", url.spec());
   EXPECT_TRUE(url.port().empty());
 }
 
 }  // namespace web