[ObjC ARC] Converts ios/chrome/browser/web:web_internal to ARC.

ios/chrome/browser/web/error_page_content.mm

 // Copyright 2012 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/web/error_page_content.h"
 
 #include <memory>
 
-#import "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/web/error_page_generator.h"
 #include "ios/web/public/referrer.h"
 #include "ui/base/page_transition_types.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 @implementation ErrorPageContent
 
 #pragma mark -
 #pragma mark CRWNativeContent methods
 
 // Override StaticHtmlNativeContent method to always force error pages to
 // try loading the URL again, because the error might have been fixed.
 - (void)reload {
   // Because we don't have the original page transition at this point, just
   // use PAGE_TRANSITION_TYPED. We can revisit if this causes problems.
   [super loadURL:[self url]
                referrer:web::Referrer()
              transition:ui::PAGE_TRANSITION_TYPED
       rendererInitiated:YES];
 }
 
 - (id)initWithLoader:(id<UrlLoader>)loader
         browserState:(web::BrowserState*)browserState
                  url:(const GURL&)url
                error:(NSError*)error
               isPost:(BOOL)isPost
          isIncognito:(BOOL)isIncognito {
   ErrorPageGenerator* generator =
-      [[[ErrorPageGenerator alloc] initWithError:error
-                                          isPost:isPost
-                                     isIncognito:isIncognito] autorelease];
+      [[ErrorPageGenerator alloc] initWithError:error
+                                         isPost:isPost
+                                    isIncognito:isIncognito];
 
-  base::scoped_nsobject<StaticHtmlViewController> HTMLViewController(
+  StaticHtmlViewController* HTMLViewController =
       [[StaticHtmlViewController alloc] initWithGenerator:generator
-                                             browserState:browserState]);
+                                             browserState:browserState];
   return [super initWithLoader:loader
       staticHTMLViewController:HTMLViewController
                            URL:url];
 }
 
 @end