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..084c07338b56e60c1c6531e37d3acfc4ac6df3e0 100644
--- a/ios/web_view/internal/translate/web_view_translate_client.mm
+++ b/ios/web_view/internal/translate/web_view_translate_client.mm
@@ -44,7 +44,8 @@ WebViewTranslateClient::WebViewTranslateClient(web::WebState* web_state)
           prefs::kAcceptLanguages)),
       translate_driver_(web_state,
                         web_state->GetNavigationManager(),
-                        translate_manager_.get()) {}
+                        translate_manager_.get(),
+                        nil) {}

[jkrcal, 2017/06/02 08:35:09]

nit: /*language_model=*/nil

Why don't you feed the model from web_view? Is it simply consistent with other
behaviour of webview and user expectations thereof?

Could you also add a comment here explaining why "nil" is used?

[jkrcal, 2017/06/02 08:36:39]

Actually, I know nothing about code style for .mm files. Take my nit merely as a
comment that just "nil" is not very clear to me.

[ramyasharma, 2017/06/05 05:07:26]

Thanks Jan. The only reason I pass nil, is because
1. I don't know if this functionality needs to be part of webview
2. Even if it does, it was not straight forward, and needed some code
duplication in webview (i am not sure if I  depend on the factory class I
introduced here). So if required I will add this in the next CL after I discuss
it with the owners of webview. 

 
 WebViewTranslateClient::~WebViewTranslateClient() = default;