Make/add virtual destructors to classes with virtual functions
diff --git a/src/core/SkPictureFlat.h b/src/core/SkPictureFlat.h
index fe9477d..db918bb 100644
--- a/src/core/SkPictureFlat.h
+++ b/src/core/SkPictureFlat.h
@@ -50,7 +50,7 @@
 class SkRefCntPlayback {
 public:
     SkRefCntPlayback();
-    ~SkRefCntPlayback();
+    virtual ~SkRefCntPlayback();
     
     int count() const { return fCount; }
     
@@ -70,6 +70,8 @@
 
 class SkTypefacePlayback : public SkRefCntPlayback {
 public:
+    virtual ~SkTypefacePlayback() {}
+
     virtual void setupBuffer(SkFlattenableReadBuffer& buffer) const {
         buffer.setTypefaceArray((SkTypeface**)fArray, fCount);
     }