diff --git a/cros/hardware_chromeos.h b/cros/hardware_chromeos.h
index 8a920ef..a64f804 100644
--- a/cros/hardware_chromeos.h
+++ b/cros/hardware_chromeos.h
@@ -68,6 +68,8 @@
   ErrorCode IsPartitionUpdateValid(
       const std::string& partition_name,
       const std::string& new_version) const override;
+  const char* GetPartitionMountOptions(
+      const std::string& partition_name) const override;
 
  private:
   friend class HardwareChromeOSTest;