Remove ScopedVector from ios/.

ios/web/webui/web_ui_ios_impl.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/web_ui_ios_impl.h"
 
 #include <stddef.h>
 
 #include "base/json/json_writer.h"
 #include "base/strings/string_util.h"
@@ skipping 125 matching lines @@
       message_callbacks_.find(message);
   if (callback != message_callbacks_.end()) {
     // Forward this message and content on.
     callback->second.Run(&args);
   }
 }
 
 // WebUIIOSImpl, protected:
 // -------------------------------------------------------
 
-void WebUIIOSImpl::AddMessageHandler(WebUIIOSMessageHandler* handler) {
+void WebUIIOSImpl::AddMessageHandler(
+    std::unique_ptr<WebUIIOSMessageHandler> handler) {
   DCHECK(!handler->web_ui());
   handler->set_web_ui(this);
   handler->RegisterMessages();
-  handlers_.push_back(handler);
+  handlers_.push_back(std::move(handler));
 }
 
 void WebUIIOSImpl::ExecuteJavascript(const base::string16& javascript) {
   web_state_->ExecuteJavaScript(javascript);
 }
 
 }  // namespace web