diff --git a/policy_manager/generic_variables.h b/policy_manager/generic_variables.h
index 2f9b996..505b180 100644
--- a/policy_manager/generic_variables.h
+++ b/policy_manager/generic_variables.h
@@ -39,7 +39,7 @@
   // GetValue() method is called.
   CopyVariable(const std::string& name, VariableMode mode, const T& ref)
       : Variable<T>(name, mode), ref_(ref) {}
-  CopyVariable(const std::string& name, const base::TimeDelta& poll_interval,
+  CopyVariable(const std::string& name, const base::TimeDelta poll_interval,
                const T& ref)
       : Variable<T>(name, poll_interval), ref_(ref) {}
 
diff --git a/policy_manager/variable.h b/policy_manager/variable.h
index eace46e..22cdd17 100644
--- a/policy_manager/variable.h
+++ b/policy_manager/variable.h
@@ -166,7 +166,7 @@
   Variable(const std::string& name, VariableMode mode)
       : BaseVariable(name, mode) {}
 
-  Variable(const std::string& name, const base::TimeDelta& poll_interval)
+  Variable(const std::string& name, const base::TimeDelta poll_interval)
       : BaseVariable(name, poll_interval) {}
 
   // Gets the current value of the variable. The current value is copied to a