[spellcheck] Don't spellcheck in removed language.

chrome/browser/spellchecker/spellcheck_service.h

 // Copyright (c) 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.
 
 #ifndef CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_SERVICE_H_
 #define CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_SERVICE_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 138 matching lines @@
   // Pass all renderers some basic initialization information.
   void InitForAllRenderers();
 
   // Reacts to a change in user preference on which languages should be used for
   // spellchecking.
   void OnSpellCheckDictionariesChanged();
 
   // Notification handler for changes to prefs::kSpellCheckUseSpellingService.
   void OnUseSpellingServiceChanged();
 
+  // Notification handler for changes to prefs::kAcceptLanguages. Removes from
+  // prefs::kSpellCheckDictionaries any languages that are not in
+  // prefs::kAcceptLanguages.
+  void OnAcceptLanguagesChanged();

[groby-ooo-7-16, 2016/02/09 02:51:33]

Do we have any listener for the on/off of the flag? 

[please use gerrit instead, 2016/02/09 20:45:49]

Yes, it's hooked directly to InitForAllRenderers():

 pref_change_registrar_.Add(
      prefs::kEnableContinuousSpellcheck,
      base::Bind(&SpellcheckService::InitForAllRenderers,
                 base::Unretained(this)));

https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/spe...

+
   // Enables the feedback sender if spelling server is available and enabled.
   // Otherwise disables the feedback sender.
   void UpdateFeedbackSenderState();
 
   PrefChangeRegistrar pref_change_registrar_;
   content::NotificationRegistrar registrar_;
 
   // A pointer to the BrowserContext which this service refers to.
   content::BrowserContext* context_;
 
   scoped_ptr<SpellCheckHostMetrics> metrics_;
 
   scoped_ptr<SpellcheckCustomDictionary> custom_dictionary_;
 
   ScopedVector<SpellcheckHunspellDictionary> hunspell_dictionaries_;
 
   scoped_ptr<spellcheck::FeedbackSender> feedback_sender_;
 
   base::WeakPtrFactory<SpellcheckService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SpellcheckService);
 };
 
 #endif  // CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_SERVICE_H_