Optionally enable SkValidatingReadBuffer in SkPictureImageFilter

src/core/SkValidatingReadBuffer.h

Index: src/core/SkValidatingReadBuffer.h
diff --git a/src/core/SkValidatingReadBuffer.h b/src/core/SkValidatingReadBuffer.h
index 28d8c34e0e99466ef535abe96fbc063319b9b537..785b15e291be4fe069004e7bf2bab010ffadd56a 100644
--- a/src/core/SkValidatingReadBuffer.h
+++ b/src/core/SkValidatingReadBuffer.h
@@ -21,7 +21,11 @@ class SkBitmap;
 class SkValidatingReadBuffer : public SkReadBuffer {
 public:
     SkValidatingReadBuffer(const void* data, size_t size);
-    virtual ~SkValidatingReadBuffer();
+    ~SkValidatingReadBuffer() override;
+
+    SkReadBuffer* clone(const void* data, size_t size) const override {
+        return new SkValidatingReadBuffer(data, size);
+    }
 
     const void* skip(size_t size) override;