[Translate] Factor out access to Accept-Languages

components/translate/core/browser/translate_prefs.cc

 // 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/core/browser/translate_prefs.h"
 
 #include <set>
 
 #include "base/prefs/pref_service.h"
 #include "base/prefs/scoped_user_pref_update.h"
@@ skipping 354 matching lines @@
 #if defined(OS_CHROMEOS)
   const char* key = preferred_languages_pref_.c_str();
 #else
   const char* key = accept_languages_pref_.c_str();
 #endif
 
   *languages = base::SplitString(prefs_->GetString(key), ",",
                                  base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
 }
 
+void TranslatePrefs::GetAcceptLanguageList(

[groby-ooo-7-16, 2015/12/16 02:48:26]

Since GetAcceptLanguageList is only used by TranslateManager::GetTargetLanguage,
and GetTargetLanguage calls TranslateDownloadManager::GetLanguageCode, I believe
it is safe to just use GetLanguageList, even though it returns the
preferred_languages on ChromeOS. 

I.e. setting the languages to 'en-US', 'ja', 'en-CA' would result in
en-US,ja,en-CA for the preferred languages, 'en-US', 'en', 'ja', 'en-CA' for the
accept-languages. The comparison in GetTargetLanguage calls GetLanguageCode on
all of them, which strips all the en-* variants to en - so the lists are
fundamentally identical.

Please let me know if I misunderstood.

+    std::vector<std::string>* languages) const {
+  DCHECK(languages);
+  DCHECK(languages->empty());
+
+  *languages = base::SplitString(prefs_->GetString(accept_languages_pref_), ",",
+                                 base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
+}
+
 void TranslatePrefs::UpdateLanguageList(
     const std::vector<std::string>& languages) {
 #if defined(OS_CHROMEOS)
   std::string languages_str = base::JoinString(languages, ",");
   prefs_->SetString(preferred_languages_pref_.c_str(), languages_str);
 #endif
 
   // Save the same language list as accept languages preference as well, but we
   // need to expand the language list, to make it more acceptable. For instance,
   // some web sites don't understand 'en-US' but 'en'. See crosbug.com/9884.
@@ skipping 239 matching lines @@
   const base::ListValue* blacklist = prefs_->GetList(pref_id);
   return (blacklist == NULL || blacklist->empty());
 }
 
 bool TranslatePrefs::IsDictionaryEmpty(const char* pref_id) const {
   const base::DictionaryValue* dict = prefs_->GetDictionary(pref_id);
   return (dict == NULL || dict->empty());
 }
 
 }  // namespace translate