Use DidFinishNavigation callback in LanguageDetectionController.

ios/web/web_state/ui/crw_web_controller.mm

 // Copyright 2012 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.
 
 #import "ios/web/web_state/ui/crw_web_controller.h"
 
 #import <WebKit/WebKit.h>
 
 #import <objc/runtime.h>
 #include <stddef.h>
@@ skipping 2844 matching lines @@
   // navigations.
   if (_dispatchingSameDocumentHashChangeEvent) {
     _dispatchingSameDocumentHashChangeEvent = NO;
   } else {
     web::NavigationItemImpl* item =
         static_cast<web::NavigationItemImpl*>([self currentNavItem]);
     DCHECK(item);
     item->SetIsCreatedFromHashChange(true);
   }
 
-  // Notify the observers.
-  _webStateImpl->OnUrlHashChanged();
   return YES;
 }
 
 - (BOOL)handleWindowHistoryBackMessage:(base::DictionaryValue*)message
                                context:(NSDictionary*)context {
   [self goDelta:-1];
   return YES;
 }
 
 - (BOOL)handleWindowHistoryForwardMessage:(base::DictionaryValue*)message
@@ skipping 78 matching lines @@
                   transition:transition];
 
   NSString* replaceWebViewJS =
       [self javaScriptToReplaceWebViewURL:pushURL stateObjectJSON:stateObject];
   base::WeakNSObject<CRWWebController> weakSelf(self);
   [self executeJavaScript:replaceWebViewJS completionHandler:^(id, NSError*) {
     if (!weakSelf || weakSelf.get()->_isBeingDestroyed)
       return;
     base::scoped_nsobject<CRWWebController> strongSelf([weakSelf retain]);
     [strongSelf optOutScrollsToTopForSubviews];
-    // Notify the observers.
-    strongSelf.get()->_webStateImpl->OnHistoryStateChanged();
     [strongSelf didFinishNavigation];
   }];
   return YES;
 }
 
 - (BOOL)handleWindowHistoryDidReplaceStateMessage:
     (base::DictionaryValue*)message
                                           context:(NSDictionary*)context {
   DCHECK(_changingHistoryState);
   _changingHistoryState = NO;
@@ skipping 2271 matching lines @@
 - (void)simulateLoadRequestWithURL:(const GURL&)URL {
   _lastRegisteredRequestURL = URL;
   _loadPhase = web::LOAD_REQUESTED;
 }
 
 - (NSString*)referrerFromNavigationAction:(WKNavigationAction*)action {
   return [action.request valueForHTTPHeaderField:kReferrerHeaderName];
 }
 
 @end