Updates language model on iOS.

ios/web_view/internal/translate/web_view_translate_client.mm

Index: ios/web_view/internal/translate/web_view_translate_client.mm
diff --git a/ios/web_view/internal/translate/web_view_translate_client.mm b/ios/web_view/internal/translate/web_view_translate_client.mm
index 20af563706b74532e3d5ca8c4c7adb1d6d251080..ddc9bed2305bb80029b705665fcf669dcd387ae1 100644
--- a/ios/web_view/internal/translate/web_view_translate_client.mm
+++ b/ios/web_view/internal/translate/web_view_translate_client.mm
@@ -34,6 +34,9 @@ DEFINE_WEB_STATE_USER_DATA_KEY(ios_web_view::WebViewTranslateClient);
 
 namespace ios_web_view {
 
+// TODO(crbug.com/729859): Support logging histogram data on detected language
+// page, by passing a valid language_model, when histogram logging is available
+// on ios/web_view.
 WebViewTranslateClient::WebViewTranslateClient(web::WebState* web_state)
     : web::WebStateObserver(web_state),
       translate_manager_(base::MakeUnique<translate::TranslateManager>(
@@ -44,7 +47,8 @@ WebViewTranslateClient::WebViewTranslateClient(web::WebState* web_state)
           prefs::kAcceptLanguages)),
       translate_driver_(web_state,
                         web_state->GetNavigationManager(),
-                        translate_manager_.get()) {}
+                        translate_manager_.get(),
+                        nullptr /* language_model */) {}
 
 WebViewTranslateClient::~WebViewTranslateClient() = default;