Add a TODO for crbug/703565

ios/web_view/internal/translate/web_view_translate_ranker_factory.cc

Index: ios/web_view/internal/translate/web_view_translate_ranker_factory.cc
diff --git a/ios/web_view/internal/translate/web_view_translate_ranker_factory.cc b/ios/web_view/internal/translate/web_view_translate_ranker_factory.cc
index f863bdf5ac01a8c01db41d72e9c952f50abfc4d9..ca08603181aedd0c6dfab95632a21bc5e1d06201 100644
--- a/ios/web_view/internal/translate/web_view_translate_ranker_factory.cc
+++ b/ios/web_view/internal/translate/web_view_translate_ranker_factory.cc
@@ -47,7 +47,9 @@ WebViewTranslateRankerFactory::BuildServiceInstanceFor(
           translate::TranslateRankerImpl::GetModelURL());
   // WebView has no consumer of translate ranker events, so don't generate them.
   ranker->EnableLogging(false);
-  return std::move(ranker);  // Fails xcode-clang compile without the move.
+
+  // TODO(crbug.com/703565): remove std::move() once Xcode 9.0+ is required.
+  return std::move(ranker);
 }
 
 }  // namespace ios_web_view