more debugging tools around BufferMapper
diff --git a/libs/surfaceflinger/LayerBitmap.h b/libs/surfaceflinger/LayerBitmap.h
index d1f7802..e673755 100644
--- a/libs/surfaceflinger/LayerBitmap.h
+++ b/libs/surfaceflinger/LayerBitmap.h
@@ -81,7 +81,7 @@
 private:
     friend class LightRefBase<Buffer>;
     Buffer(const Buffer& rhs);
-    ~Buffer();
+    virtual ~Buffer();
     Buffer& operator = (const Buffer& rhs);
     const Buffer& operator = (const Buffer& rhs) const;