BUG=skia:
Review URL: https://codereview.chromium.org/894693003
diff --git a/include/core/SkClipStack.h b/include/core/SkClipStack.h
index 79789dc..3f79f92 100644
--- a/include/core/SkClipStack.h
+++ b/include/core/SkClipStack.h
@@ -24,7 +24,7 @@
// (i.e., the fSaveCount in force when it was added). Restores are thus
// implemented by removing clips from fDeque that have an fSaveCount larger
// then the freshly decremented count.
-class SK_API SkClipStack {
+class SK_API SkClipStack : public SkNVRefCnt<SkClipStack> {
public:
enum BoundsType {
// The bounding box contains all the pixels that can be written to