Use DidFinishNavigation callback in LanguageDetectionController.

ios/web/public/test/fakes/crw_test_web_state_observer.mm

Index: ios/web/public/test/fakes/crw_test_web_state_observer.mm
diff --git a/ios/web/public/test/fakes/crw_test_web_state_observer.mm b/ios/web/public/test/fakes/crw_test_web_state_observer.mm
index 755753f1660e00ca3a68a520de3069f565affb6f..b7e785c0fddfb9d6d77a9be4534878e64e5dd16f 100644
--- a/ios/web/public/test/fakes/crw_test_web_state_observer.mm
+++ b/ios/web/public/test/fakes/crw_test_web_state_observer.mm
@@ -24,8 +24,6 @@ TestUpdateFaviconUrlCandidatesInfo::~TestUpdateFaviconUrlCandidatesInfo() =
   std::unique_ptr<web::TestLoadPageInfo> _loadPageInfo;
   // Arguments passed to |webStateDidDismissInterstitial:|.
   std::unique_ptr<web::TestDismissInterstitialInfo> _dismissInterstitialInfo;
-  // Arguments passed to |webStateDidChangeURLHash:|.
-  std::unique_ptr<web::TestChangeUrlHashInfo> _changeUrlHashInfo;
   // Arguments passed to |webStateDidChangeHistoryState:|.
   std::unique_ptr<web::TestChangeHistoryStateInfo> _changeHistoryStateInfo;
   // Arguments passed to |webState:didChangeLoadingProgress:|.
@@ -66,10 +64,6 @@ TestUpdateFaviconUrlCandidatesInfo::~TestUpdateFaviconUrlCandidatesInfo() =
   return _dismissInterstitialInfo.get();
 }
 
-- (web::TestChangeUrlHashInfo*)changeUrlHashInfo {
-  return _changeUrlHashInfo.get();
-}
-
 - (web::TestChangeHistoryStateInfo*)changeHistoryStateInfo {
   return _changeHistoryStateInfo.get();
 }
@@ -136,11 +130,6 @@ TestUpdateFaviconUrlCandidatesInfo::~TestUpdateFaviconUrlCandidatesInfo() =
   _dismissInterstitialInfo->web_state = webState;
 }
 
-- (void)webStateDidChangeURLHash:(web::WebState*)webState {
-  _changeUrlHashInfo = base::MakeUnique<web::TestChangeUrlHashInfo>();
-  _changeUrlHashInfo->web_state = webState;
-}
-
 - (void)webStateDidChangeHistoryState:(web::WebState*)webState {
   _changeHistoryStateInfo = base::MakeUnique<web::TestChangeHistoryStateInfo>();
   _changeHistoryStateInfo->web_state = webState;