Updates language model on iOS.

ios/chrome/browser/browsing_data/ios_chrome_browsing_data_remover.mm

Index: ios/chrome/browser/browsing_data/ios_chrome_browsing_data_remover.mm
diff --git a/ios/chrome/browser/browsing_data/ios_chrome_browsing_data_remover.mm b/ios/chrome/browser/browsing_data/ios_chrome_browsing_data_remover.mm
index 1600961322b0c4fb083f462fab1c96bb09539524..b4eb8e04656a39318d1972cc1b038f7fdd6c646a 100644
--- a/ios/chrome/browser/browsing_data/ios_chrome_browsing_data_remover.mm
+++ b/ios/chrome/browser/browsing_data/ios_chrome_browsing_data_remover.mm
@@ -24,6 +24,7 @@
 #include "components/prefs/pref_service.h"
 #include "components/search_engines/template_url_service.h"
 #include "components/sessions/core/tab_restore_service.h"
+#include "components/translate/core/browser/language_model.h"
 #include "ios/chrome/browser/application_context.h"
 #include "ios/chrome/browser/autofill/personal_data_manager_factory.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
@@ -33,6 +34,7 @@
 #include "ios/chrome/browser/passwords/ios_chrome_password_store_factory.h"
 #include "ios/chrome/browser/search_engines/template_url_service_factory.h"
 #include "ios/chrome/browser/sessions/ios_chrome_tab_restore_service_factory.h"
+#include "ios/chrome/browser/translate/language_model_factory.h"
 #include "ios/chrome/browser/web_data_service_factory.h"
 #include "ios/net/http_cache_helper.h"
 #include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
@@ -350,6 +352,13 @@ void IOSChromeBrowsingDataRemover::RemoveImpl(int remove_mask) {
   UMA_HISTOGRAM_ENUMERATION(
       "History.ClearBrowsingData.UserDeletedCookieOrCache", choice,
       MAX_CHOICE_VALUE);
+
+  // Remove language model history.

[martis, 2017/06/01 06:49:21]

I believe the language model should only be cleared if the user requests a
history clear (as opposed to e.g. a cookie clear); at least, this is the
behavior for non-iOS Chrome. 

This logic should be moved to line 249.

[ramyasharma, 2017/06/02 07:20:24]

Thanks, good catch. 

+  translate::LanguageModel* language_model =
+      translate::LanguageModelFactory::GetForBrowserState(browser_state_);
+  if (language_model) {
+    language_model->ClearHistory(delete_begin_, delete_end_);
+  }
 }
 
 void IOSChromeBrowsingDataRemover::AddObserver(Observer* observer) {