Clean up year+ old prefs in iOS/

This patch means cleaning up old pref that have passed over year+.
A follow up to that CL.
(https://chromium-review.googlesource.com/c/chromium/src/+/1264343)

Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: Ib1949419b5b2df9b6906d5f5b7d100f5d5a7046c
Reviewed-on: https://chromium-review.googlesource.com/c/1278455Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Jaeyong Bae <jdragon.bae@gmail.com>
Cr-Commit-Position: refs/heads/master@{#600003}

components/translate/core/browser/translate_prefs.cc

@@ -897,48 +897,6 @@ void TranslatePrefs::RegisterProfilePrefs(
 #endif
 }
 
-// static
-void TranslatePrefs::MigrateUserPrefs(PrefService* user_prefs,
-                                      const char* accept_languages_pref) {
-  // Old format of kPrefTranslateWhitelists
-  // - original language -> list of target langs to auto-translate
-  // - list of langs is in order of being enabled i.e. last in list is the
-  //   most recent language that user enabled via
-  //   Always translate |source_lang| to |target_lang|"
-  // - this results in a one-to-n relationship between source lang and target
-  //   langs.
-  // New format:
-  // - original language -> one target language to auto-translate
-  // - each time that the user enables the "Always translate..." option, that
-  //   target lang overwrites the previous one.
-  // - this results in a one-to-one relationship between source lang and target
-  //   lang
-  // - we replace old list of target langs with the last target lang in list,
-  //   assuming the last (i.e. most recent) target lang is what user wants to
-  //   keep auto-translated.
-  DictionaryPrefUpdate update(user_prefs, kPrefTranslateWhitelists);
-  base::DictionaryValue* dict = update.Get();
-  if (dict && !dict->empty()) {
-    base::DictionaryValue::Iterator iter(*dict);
-    while (!iter.IsAtEnd()) {
-      const base::ListValue* list = nullptr;
-      if (!iter.value().GetAsList(&list) || !list)
-        break;  // Dictionary has either been migrated or new format.
-      std::string key = iter.key();
-      // Advance the iterator before removing the current element.
-      iter.Advance();
-      std::string target_lang;
-      if (list->empty() ||
-          !list->GetString(list->GetSize() - 1, &target_lang) ||
-          target_lang.empty()) {
-        dict->Remove(key, nullptr);
-      } else {
-        dict->SetString(key, target_lang);
-      }
-    }
-  }
-}
-
 void TranslatePrefs::MigrateSitesBlacklist() {
   // Migration should only be neccessary once but there could still be old
   // Chrome instances that sync the old preference, so do it once per

components/translate/core/browser/translate_prefs.h

@@ -321,8 +321,6 @@ class TranslatePrefs {
   void MigrateSitesBlacklist();
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
-  static void MigrateUserPrefs(PrefService* user_prefs,
-                               const char* accept_languages_pref);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(TranslatePrefsTest, UpdateLanguageList);

ios/chrome/browser/pref_names.cc

@@ -132,11 +132,6 @@ const char kSigninLastAccounts[] = "ios.signin.last_accounts";
 // accounts was migrated to use account ids instead of emails.
 const char kSigninLastAccountsMigrated[] = "ios.signin.last_accounts_migrated";
 
-// String which contains the user id of the user signed in with shared
-// authentication.
-const char kSigninSharedAuthenticationUserId[] =
-    "ios.signin.shared_authentication_user_id";
-
 // Boolean which indicates if user should be prompted to sign in again
 // when a new tab is created.
 const char kSigninShouldPromptForSigninAgain[] =

ios/chrome/browser/pref_names.h

@@ -44,7 +44,6 @@ extern const char kShowMemoryDebuggingTools[];
 
 extern const char kSigninLastAccounts[];
 extern const char kSigninLastAccountsMigrated[];
-extern const char kSigninSharedAuthenticationUserId[];
 extern const char kSigninShouldPromptForSigninAgain[];
 
 extern const char kOmniboxGeolocationAuthorizationState[];

ios/chrome/browser/prefs/browser_prefs.mm

@@ -176,12 +176,6 @@ void MigrateObsoleteLocalStatePrefs(PrefService* prefs) {
 
 // This method should be periodically pruned of year+ old migrations.
 void MigrateObsoleteBrowserStatePrefs(PrefService* prefs) {
-  // Added 07/2014.
-  translate::TranslatePrefs::MigrateUserPrefs(prefs, prefs::kAcceptLanguages);
-
-  // Added 08/2015.
-  prefs->ClearPref(::prefs::kSigninSharedAuthenticationUserId);
-
   // Added 01/2018.
   prefs->ClearPref(::prefs::kNtpShownPage);
 

ios/chrome/browser/signin/authentication_service.mm

@@ -94,8 +94,6 @@ AuthenticationService::~AuthenticationService() {
 // static
 void AuthenticationService::RegisterPrefs(
     user_prefs::PrefRegistrySyncable* registry) {
-  registry->RegisterStringPref(prefs::kSigninSharedAuthenticationUserId,
-                               std::string());
   registry->RegisterBooleanPref(prefs::kSigninShouldPromptForSigninAgain,
                                 false);
   registry->RegisterListPref(prefs::kSigninLastAccounts);