Use DidFinishNavigation callback in LanguageDetectionController.

components/translate/ios/browser/language_detection_controller.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 "components/translate/ios/browser/language_detection_controller.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/time/time.h"
 #include "components/prefs/pref_member.h"
 #include "components/translate/core/common/translate_pref_names.h"
 #include "components/translate/core/language_detection/language_detection_util.h"
 #import "components/translate/ios/browser/js_language_detection_manager.h"
 #include "components/translate/ios/browser/string_clipping_util.h"
 #import "ios/web/public/url_scheme_util.h"
+#include "ios/web/public/web_state/navigation_context.h"
 #include "ios/web/public/web_state/web_state.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 namespace translate {
 
 namespace {
 // Name for the UMA metric used to track text extraction time.
@@ skipping 101 matching lines @@
 }
 
 // web::WebStateObserver implementation:
 
 void LanguageDetectionController::PageLoaded(
     web::PageLoadCompletionStatus load_completion_status) {
   if (load_completion_status == web::PageLoadCompletionStatus::SUCCESS)
     StartLanguageDetection();
 }
 
-void LanguageDetectionController::UrlHashChanged() {
-  StartLanguageDetection();
-}
-
-void LanguageDetectionController::HistoryStateChanged() {
-  StartLanguageDetection();
+void LanguageDetectionController::DidFinishNavigation(
+    web::NavigationContext* navigation_context) {
+  if (navigation_context->IsSamePage())
+    StartLanguageDetection();
 }
 
 void LanguageDetectionController::WebStateDestroyed() {
   web_state()->RemoveScriptCommandCallback(kCommandPrefix);
 }
 
 }  // namespace translate