[C++] Stop using shared_ptr<string> in SimpleVar
diff --git a/var.h b/var.h
index 29b0517..0962f89 100644
--- a/var.h
+++ b/var.h
@@ -63,7 +63,7 @@
 
 class SimpleVar : public Var {
  public:
-  SimpleVar(shared_ptr<string> v, VarOrigin origin);
+  SimpleVar(const string& v, VarOrigin origin);
 
   virtual const char* Flavor() const {
     return "simple";
@@ -72,9 +72,6 @@
     return origin_;
   }
 
-  virtual shared_ptr<string> Eval(Evaluator*) const override {
-    return v_;
-  }
   virtual void Eval(Evaluator* ev, string* s) const override;
 
   virtual void AppendVar(Evaluator* ev, Value* v);
@@ -84,7 +81,7 @@
   virtual string DebugString() const override;
 
  private:
-  shared_ptr<string> v_;
+  string v_;
   VarOrigin origin_;
 };