[ARC] [Split this CL] Convert ios/web/webui to ARC.

ios/web/webui/shared_resources_data_source_ios.mm

 // Copyright 2014 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/webui/shared_resources_data_source_ios.h"
 
 #include <stddef.h>
 
 #include "base/logging.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/strings/string_util.h"
 #include "ios/web/public/web_client.h"
 #include "net/base/mime_util.h"
 #include "ui/base/webui/web_ui_util.h"
 #include "ui/resources/grit/webui_resources.h"
 #include "ui/resources/grit/webui_resources_map.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 namespace {
 
 // Value duplicated from content/public/common/url_constants.h
 // TODO(stuartmorgan): Revisit how to share this in a more maintainable way.
 const char kWebUIResourcesHost[] = "resources";
 
 int PathToIDR(const std::string& path) {
   int idr = -1;
@@ skipping 37 matching lines @@
 }
 
 std::string SharedResourcesDataSourceIOS::GetMimeType(
     const std::string& path) const {
   std::string mime_type;
   net::GetMimeTypeFromFile(base::FilePath().AppendASCII(path), &mime_type);
   return mime_type;
 }
 
 }  // namespace web