Implement ios language detection logging.

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/feature_list.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "components/infobars/core/infobar.h"
 #include "components/metrics/proto/translate_event.pb.h"
 #include "components/prefs/pref_service.h"
 #include "components/sync/driver/sync_driver_switches.h"
 #include "components/sync/protocol/user_event_specifics.pb.h"
 #include "components/sync/user_events/user_event_service.h"
 #include "components/translate/core/browser/page_translated_details.h"
 #include "components/translate/core/browser/translate_accept_languages.h"
 #include "components/translate/core/browser/translate_infobar_delegate.h"
 #include "components/translate/core/browser/translate_manager.h"
 #include "components/translate/core/browser/translate_prefs.h"
 #include "components/translate/core/browser/translate_step.h"
 #include "components/translate/core/common/language_detection_details.h"
+#include "components/translate/core/common/language_detection_logging_helper.h"
 #include "components/translate/core/common/translation_logging_helper.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/infobars/infobar.h"
 #include "ios/chrome/browser/infobars/infobar_controller.h"
 #include "ios/chrome/browser/infobars/infobar_manager_impl.h"
 #include "ios/chrome/browser/pref_names.h"
 #import "ios/chrome/browser/sync/ios_user_event_service_factory.h"
 #import "ios/chrome/browser/translate/after_translate_infobar_controller.h"
 #import "ios/chrome/browser/translate/before_translate_infobar_controller.h"
 #include "ios/chrome/browser/translate/language_model_factory.h"
@@ skipping 150 matching lines @@
       ios::ChromeBrowserState::FromBrowserState(
           web_state()->GetBrowserState()));
 }
 
 int ChromeIOSTranslateClient::GetInfobarIconID() const {
   return IDR_IOS_INFOBAR_TRANSLATE;
 }
 
 void ChromeIOSTranslateClient::RecordLanguageDetectionEvent(
     const translate::LanguageDetectionDetails& details) const {
-  // TODO(crbug.com/728491): Implement this.
+  if (!base::FeatureList::IsEnabled(switches::kSyncUserLanguageDetectionEvents))
+    return;
+
+  syncer::UserEventService* const user_event_service =
+      IOSUserEventServiceFactory::GetForBrowserState(
+          ios::ChromeBrowserState::FromBrowserState(
+              web_state()->GetBrowserState()));
+  const auto* const item =
+      web_state()->GetNavigationManager()->GetLastCommittedItem();
+
+  // If entry is null, we don't record the page.
+  // The navigation entry can be null in situations like download or initial
+  // blank page.
+  if (item != nullptr &&
+      TranslateServiceIOS::IsTranslatableURL(item->GetVirtualURL())) {
+    user_event_service->RecordUserEvent(
+        translate::ConstructLanguageDetectionEvent(
+            item->GetTimestamp().ToInternalValue(), details));
+  }
 }
 
 bool ChromeIOSTranslateClient::IsTranslatableURL(const GURL& url) {
   return TranslateServiceIOS::IsTranslatableURL(url);
 }
 
 void ChromeIOSTranslateClient::ShowReportLanguageDetectionErrorUI(
     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();
 }