Add SK_API to SkString free functions.

Functions in include/ are meant to be publicly accessible API.

Change-Id: I4bb78021fc2250b5e1d026c7bd3098374048d8a7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/805216
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
1 file changed