Get HelloWorld example running again

Change-Id: I5956f7c52d265d9f52dd061f1555c54ad092fe76
Reviewed-on: https://skia-review.googlesource.com/57101
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/example/HelloWorld.h b/example/HelloWorld.h
index d3fc7cf..05d9b81 100644
--- a/example/HelloWorld.h
+++ b/example/HelloWorld.h
@@ -62,10 +62,10 @@
     // support framework
     DeviceType fType;
     sk_sp<SkSurface> fRasterSurface;
-    GrContext* fContext;
+    sk_sp<GrContext> fContext;
     sk_sp<SkSurface> fGpuSurface;
     AttachmentInfo fAttachmentInfo;
-    const GrGLInterface* fInterface;
+    sk_sp<const GrGLInterface> fInterface;
 
     typedef SkOSWindow INHERITED;
 };