Converts parts of ios/web to ARC

ios/web/interstitials/native_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.
 
 #include "ios/web/interstitials/native_web_interstitial_impl.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "ios/web/public/interstitials/web_interstitial_delegate.h"
 #import "ios/web/public/web_state/ui/crw_generic_content_view.h"
 #include "ios/web/web_state/web_state_impl.h"
 #include "ui/gfx/geometry/size.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 // static
 WebInterstitial* WebInterstitial::CreateNativeInterstitial(
     WebState* web_state,
     bool new_navigation,
     const GURL& url,
     std::unique_ptr<NativeWebInterstitialDelegate> delegate) {
   WebStateImpl* web_state_impl = static_cast<WebStateImpl*>(web_state);
   return new NativeWebInterstitialImpl(web_state_impl, new_navigation, url,
@@ skipping 28 matching lines @@
   return delegate_.get();
 }
 
 void NativeWebInterstitialImpl::EvaluateJavaScript(
     NSString* script,
     JavaScriptCompletion completionHandler) {
   NOTREACHED() << "JavaScript cannot be evaluated on native interstitials.";
 }
 
 }  // namespace web