Converts parts of ios/web to ARC

ios/web/interstitials/html_web_interstitial_impl.mm

 // Copyright 2015 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/interstitials/html_web_interstitial_impl.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ios/web/interstitials/web_interstitial_facade_delegate.h"
 #include "ios/web/public/interstitials/web_interstitial_delegate.h"
 #include "ios/web/public/web_state/ui/crw_web_view_content_view.h"
 #import "ios/web/public/web_view_creation_util.h"
 #import "ios/web/web_state/ui/web_view_js_utils.h"
 #include "ios/web/web_state/web_state_impl.h"
 #import "net/base/mac/url_conversions.h"
 #include "ui/gfx/geometry/size.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 // The delegate of the web view that is used to display the HTML content.
 // It intercepts JavaScript-triggered commands and forwards them
 // to the interstitial.
 @interface CRWWebInterstitialImplWKWebViewDelegate
     : NSObject<WKNavigationDelegate>
 // Initializes a CRWWebInterstitialImplWKWebViewDelegate which will
 // forward JavaScript commands from its WKWebView to |interstitial|.
 - (instancetype)initWithInterstitial:
     (web::HtmlWebInterstitialImpl*)interstitial;
 @end
@@ skipping 95 matching lines @@
   return delegate_.get();
 }
 
 void HtmlWebInterstitialImpl::EvaluateJavaScript(
     NSString* script,
     JavaScriptCompletion completionHandler) {
   web::EvaluateJavaScript(web_view_, script, completionHandler);
 }
 
 }  // namespace web