PART1: Initiated the SignedSettings refactoring.

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

 // Copyright (c) 2011 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 "chrome/browser/ui/webui/options/chromeos/system_settings_provider.h"
 
 #include <string>
 
 #include "base/i18n/rtl.h"
 #include "base/lazy_instance.h"
@@ skipping 196 matching lines @@
     if (!in_value || !in_value->IsType(Value::TYPE_STRING) ||
         !in_value->GetAsString(&value))
       return;
     const icu::TimeZone* timezone = GetTimezone(value);
     if (!timezone)
       return;
     system::TimezoneSettings::GetInstance()->SetTimezone(*timezone);
   }
 }
 
-bool SystemSettingsProvider::Get(const std::string& path,
-                                 Value** out_value) const {
+const base::Value* SystemSettingsProvider::Get(const std::string& path) const {
   if (path == kSystemTimezone) {
-    *out_value = Value::CreateStringValue(GetKnownTimezoneID(
-        system::TimezoneSettings::GetInstance()->GetTimezone()));
-    return true;
+    // TODO(pastarmovj): Cache this in the local_state instead of locally.
+    system_timezone_.reset(base::Value::CreateStringValue(GetKnownTimezoneID(
+        system::TimezoneSettings::GetInstance()->GetTimezone())));
+    return system_timezone_.get();
   }
-  return false;
+  return NULL;
+}
+
+// The timezone is always trusted.
+bool SystemSettingsProvider::GetTrusted(const std::string& path,
+                                        const base::Closure& callback) const {
+  return true;
 }
 
 bool SystemSettingsProvider::HandlesSetting(const std::string& path) const {
   return path == kSystemTimezone;
 }
 
 void SystemSettingsProvider::TimezoneChanged(const icu::TimeZone& timezone) {
   // Fires system setting change notification.
   CrosSettings::Get()->FireObservers(kSystemTimezone);
 }
@@ skipping 75 matching lines @@
     const icu::TimeZone* known_timezone = *iter;
     if (known_timezone->hasSameRules(timezone))
       return GetTimezoneID(*known_timezone);
   }
 
   // Not able to find a matching timezone in our list.
   return string16();
 }
 
 }  // namespace chromeos