Add VirtualLightRefBase

Change-Id: I040db87d9e87ba0584e7e5bdd72f0c319a522fa1
diff --git a/include/utils/RefBase.h b/include/utils/RefBase.h
index cbfe13a..8e15c19 100644
--- a/include/utils/RefBase.h
+++ b/include/utils/RefBase.h
@@ -203,6 +203,13 @@
     mutable volatile int32_t mCount;
 };
 
+// This is a wrapper around LightRefBase that simply enforces a virtual
+// destructor to eliminate the template requirement of LightRefBase
+class VirtualLightRefBase : public LightRefBase<VirtualLightRefBase> {
+public:
+    virtual ~VirtualLightRefBase() {}
+};
+
 // ---------------------------------------------------------------------------
 
 template <typename T>