PART1: Initiated the SignedSettings refactoring.

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

Index: chrome/browser/ui/webui/options/chromeos/system_settings_provider.h
diff --git a/chrome/browser/ui/webui/options/chromeos/system_settings_provider.h b/chrome/browser/ui/webui/options/chromeos/system_settings_provider.h
index fe2ae1ecd43c318d180c9eb5715bff0099d12a4d..e3f95b0a4e535a5bf5a0f0ae56bdd67848fb20d6 100644
--- a/chrome/browser/ui/webui/options/chromeos/system_settings_provider.h
+++ b/chrome/browser/ui/webui/options/chromeos/system_settings_provider.h
@@ -7,6 +7,7 @@
 
 #include <vector>
 
+#include "base/callback.h"
 #include "base/string16.h"
 #include "chrome/browser/chromeos/cros_settings_provider.h"
 #include "chrome/browser/chromeos/system/timezone_settings.h"
@@ -15,6 +16,7 @@
 namespace base {
 class Value;
 class ListValue;
+class StringValue;
 }
 
 namespace chromeos {
@@ -26,8 +28,9 @@ class SystemSettingsProvider : public CrosSettingsProvider,
   virtual ~SystemSettingsProvider();
 
   // CrosSettingsProvider overrides.
-  virtual bool Get(const std::string& path,
-                   base::Value** out_value) const OVERRIDE;
+  virtual const base::Value* Get(const std::string& path) const OVERRIDE;
+  virtual bool GetTrusted(const std::string& path,
+                          const base::Closure& callback) const OVERRIDE;
   virtual bool HandlesSetting(const std::string& path) const OVERRIDE;
 
   // Overridden from TimezoneSettings::Observer:
@@ -60,6 +63,8 @@ class SystemSettingsProvider : public CrosSettingsProvider,
 
   // Timezones.
   std::vector<icu::TimeZone*> timezones_;
+  // TODO(pastarmovj): This will be cached in the local_state PrefStore soon.
+  mutable scoped_ptr<base::StringValue> system_timezone_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemSettingsProvider);
 };