Add SK_API to SkCanvas::ImageSetEntry to fix Chrome roll

Change-Id: I9c73ff0ca6badb9c357f75c6054286d5a787a324
Reviewed-on: https://skia-review.googlesource.com/c/172403
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
Auto-Submit: Brian Salomon <bsalomon@google.com>
1 file changed