[ObjC ARC] Converts ios/web/public/test/fakes:fakes to ARC.

ios/web/public/test/fakes/test_native_content.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/test/fakes/test_native_content.h"
 
-#import "base/mac/scoped_nsobject.h"
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
 
 @implementation TestNativeContent {
   GURL _URL;
   GURL _virtualURL;
-  base::scoped_nsobject<UIView> _view;
+  UIView* _view;
 }
 - (instancetype)initWithURL:(const GURL&)URL
                  virtualURL:(const GURL&)virtualURL {
   self = [super init];
   if (self) {
     _URL = URL;
     _virtualURL = virtualURL;
   }
   return self;
 }
@@ skipping 24 matching lines @@
 - (void)handleLowMemory {
 }
 
 - (BOOL)isViewAlive {
   return YES;
 }
 
 - (void)reload {
 }
 @end