Fix vulkan build

TBR=bsalomon@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2193883002

Review-Url: https://codereview.chromium.org/2193883002
diff --git a/src/gpu/vk/GrVkBuffer.h b/src/gpu/vk/GrVkBuffer.h
index bb529b3..473a837 100644
--- a/src/gpu/vk/GrVkBuffer.h
+++ b/src/gpu/vk/GrVkBuffer.h
@@ -20,7 +20,7 @@
  */
 class GrVkBuffer : public SkNoncopyable {
 public:
-    ~GrVkBuffer() {
+    virtual ~GrVkBuffer() {
         // either release or abandon should have been called by the owner of this object.
         SkASSERT(!fResource);
     }