[ios] Add TODO to record usages of "return std::move(foo)" pattern.

ios/chrome/browser/translate/chrome_ios_translate_client.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/chrome/browser/translate/chrome_ios_translate_client.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 68 matching lines @@
       break;
     case translate::TRANSLATE_STEP_TRANSLATING:
     case translate::TRANSLATE_STEP_TRANSLATE_ERROR:
       controller.reset([[TranslateMessageInfoBarController alloc]
           initWithDelegate:infobar.get()]);
       break;
     default:
       NOTREACHED();
   }
   infobar->SetController(controller);
+  // TODO(crbug.com/703565): remove std::move() once Xcode 9.0+ is required.
   return std::move(infobar);
 }
 
 void ChromeIOSTranslateClient::ShowTranslateUI(
     translate::TranslateStep step,
     const std::string& source_language,
     const std::string& target_language,
     translate::TranslateErrors::Type error_type,
     bool triggered_from_menu) {
   DCHECK(web_state());
@@ skipping 48 matching lines @@
     const GURL& report_url) {
   NOTREACHED();
 }
 
 void ChromeIOSTranslateClient::WebStateDestroyed() {
   // Translation process can be interrupted.
   // Destroying the TranslateManager now guarantees that it never has to deal
   // with nullptr WebState.
   translate_manager_.reset();
 }