DeviceSettingsProvider's write path uses OwnerSettingsService now.

chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc

Index: chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
diff --git a/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc b/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
index ea82e03b7b72912c0736dbfb4921433f737a101d..abb7ae93d4e3ead4d0aabccb317cd3494dfbfd1e 100644
--- a/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
+++ b/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
@@ -224,6 +224,24 @@ bool OwnerSettingsServiceChromeOS::Set(const std::string& setting,
   return true;
 }
 
+bool OwnerSettingsServiceChromeOS::SetPolicy(
+    scoped_ptr<enterprise_management::PolicyData> policy) {
+  if (!IsOwner() && !IsOwnerInTests(user_id_))
+    return false;
+  if (policy->username() != user_id_) {
+    LOG(ERROR) << "Username mismatch: " << policy->username() << " vs. "
+               << user_id_;
+    return false;
+  }
+  CHECK(device_settings_.ParseFromString(policy->policy_value()));
+  FOR_EACH_OBSERVER(OwnerSettingsService::Observer,
+                    observers_,
+                    OnTentativeChangesInPolicy(*policy));
+  has_pending_changes_ = true;
+  StoreDeviceSettings();
+  return true;
+}
+
 void OwnerSettingsServiceChromeOS::Observe(
     int type,
     const content::NotificationSource& source,