RefCounted types should not have public destructors, delegate cleanup

content/common/gpu/image_transport_surface.h

Index: content/common/gpu/image_transport_surface.h
diff --git a/content/common/gpu/image_transport_surface.h b/content/common/gpu/image_transport_surface.h
index 307a11ea3a71d86b451873261fc8050363998673..3c6e3d7c7b34f7da41294ff542e69e38f41069e2 100644
--- a/content/common/gpu/image_transport_surface.h
+++ b/content/common/gpu/image_transport_surface.h
@@ -59,7 +59,6 @@ class GLES2Decoder;
 class ImageTransportSurface {
  public:
   ImageTransportSurface();
-  virtual ~ImageTransportSurface();
 
   virtual void OnNewSurfaceACK(
       uint64 surface_id, TransportDIB::Handle surface_handle) = 0;
@@ -80,6 +79,9 @@ class ImageTransportSurface {
                         const gfx::Rect& new_damage_rect,
                         std::vector<gfx::Rect>* regions);
 
+ protected:
+  virtual ~ImageTransportSurface();
+
  private:
   DISALLOW_COPY_AND_ASSIGN(ImageTransportSurface);
 };