Added a timezone policy and pyauto tests for it.

chrome/browser/chromeos/settings/device_settings_provider.cc

Index: chrome/browser/chromeos/settings/device_settings_provider.cc
diff --git a/chrome/browser/chromeos/settings/device_settings_provider.cc b/chrome/browser/chromeos/settings/device_settings_provider.cc
index 0c1432e6b672076dcff911d2466be77d6768a1d4..b8f0e0eaecaeba5081dd2482c2982a359c0e2212 100644
--- a/chrome/browser/chromeos/settings/device_settings_provider.cc
+++ b/chrome/browser/chromeos/settings/device_settings_provider.cc
@@ -61,6 +61,7 @@ const char* kKnownSettings[] = {
   kSignedDataRoamingEnabled,
   kStartUpUrls,
   kStatsReportingPref,
+  kSystemTimezonePolicy,
 };
 
 // Upper bound for number of retries to fetch a signed setting.
@@ -298,6 +299,7 @@ void DeviceSettingsProvider::SetInPolicy() {
     //   kScreenSaverExtensionId
     //   kScreenSaverTimeout
     //   kStartUpUrls
+    //   kSystemTimezonePolicy
 
     NOTREACHED();
   }
@@ -526,6 +528,14 @@ void DeviceSettingsProvider::DecodeGenericPolicies(
       policy.has_release_channel() &&
       policy.release_channel().has_release_channel_delegated() &&
       policy.release_channel().release_channel_delegated());
+
+  if (policy.has_system_timezone()) {
+    if (policy.system_timezone().has_timezone()) {
+      new_values_cache->SetString(
+          kSystemTimezonePolicy,
+          policy.system_timezone().timezone());
+    }
+  }
 }
 
 void DeviceSettingsProvider::UpdateValuesCache() {