PART1: Initiated the SignedSettings refactoring.

chrome/browser/ui/webui/options/chromeos/accounts_options_handler.cc

Index: chrome/browser/ui/webui/options/chromeos/accounts_options_handler.cc
diff --git a/chrome/browser/ui/webui/options/chromeos/accounts_options_handler.cc b/chrome/browser/ui/webui/options/chromeos/accounts_options_handler.cc
index dde7bc625bada62a713e0c9bfe43a13e8dddbd2b..daccc51e0bf5c6f689a723594245fc6680d97209 100644
--- a/chrome/browser/ui/webui/options/chromeos/accounts_options_handler.cc
+++ b/chrome/browser/ui/webui/options/chromeos/accounts_options_handler.cc
@@ -9,6 +9,7 @@
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/chromeos/cros_settings.h"
 #include "chrome/browser/chromeos/cros_settings_names.h"
 #include "chrome/browser/chromeos/login/authenticator.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
@@ -20,8 +21,7 @@
 
 namespace chromeos {
 
-AccountsOptionsHandler::AccountsOptionsHandler()
-    : CrosOptionsPageUIHandler(new UserCrosSettingsProvider) {
+AccountsOptionsHandler::AccountsOptionsHandler() {
 }
 
 AccountsOptionsHandler::~AccountsOptionsHandler() {
@@ -58,8 +58,10 @@ void AccountsOptionsHandler::GetLocalizedValues(
       IDS_OPTIONS_ACCOUNTS_ADD_USERS));
   localized_strings->SetString("owner_only", l10n_util::GetStringUTF16(
       IDS_OPTIONS_ACCOUNTS_OWNER_ONLY));
-  localized_strings->SetString("owner_user_id", UTF8ToUTF16(
-      UserCrosSettingsProvider::cached_owner()));
+
+  std::string owner;
+  CrosSettings::Get()->GetString(kDeviceOwner, &owner);
+  localized_strings->SetString("owner_user_id", UTF8ToUTF16(owner));
 
   localized_strings->SetString("current_user_is_owner",
       UserManager::Get()->current_user_is_owner() ?
@@ -72,17 +74,13 @@ void AccountsOptionsHandler::GetLocalizedValues(
           ASCIIToUTF16("true") : ASCIIToUTF16("false"));
 }
 
-UserCrosSettingsProvider* AccountsOptionsHandler::users_settings() const {
-  return static_cast<UserCrosSettingsProvider*>(settings_provider_.get());
-}
-
 void AccountsOptionsHandler::WhitelistUser(const ListValue* args) {
   std::string email;
   if (!args->GetString(0, &email)) {
     return;
   }
 
-  users_settings()->WhitelistUser(Authenticator::Canonicalize(email));
+  UserCrosSettingsProvider::WhitelistUser(Authenticator::Canonicalize(email));
 }
 
 void AccountsOptionsHandler::UnwhitelistUser(const ListValue* args) {
@@ -91,7 +89,7 @@ void AccountsOptionsHandler::UnwhitelistUser(const ListValue* args) {
     return;
   }
 
-  users_settings()->UnwhitelistUser(Authenticator::Canonicalize(email));
+  UserCrosSettingsProvider::UnwhitelistUser(Authenticator::Canonicalize(email));
   UserManager::Get()->RemoveUser(email, NULL);
 }
 
@@ -102,7 +100,9 @@ void AccountsOptionsHandler::WhitelistExistingUsers(const ListValue* args) {
   for (UserVector::const_iterator it = users.begin();
        it < users.end(); ++it) {
     const std::string& email = it->email();
-    if (!UserCrosSettingsProvider::IsEmailInCachedWhitelist(email)) {
+    const ListValue *user_list;
+    CrosSettings::Get()->GetList(kAccountsPrefUsers, &user_list);
+    if (user_list->Find(StringValue(email)) != user_list->end()) {
       DictionaryValue* user_dict = new DictionaryValue;
       user_dict->SetString("name", it->GetDisplayName());
       user_dict->SetString("email", email);