Make the GrSmallPathAtlasMgr a flush-time object

This will allow the small path renderer to be used w/ DDLs.

This is broken out of the omnibus CL:

https://skia-review.googlesource.com/c/skia/+/307776 (Split the small path renderer into record-time and flush-time pieces)

Bug: 1108408
Change-Id: I64cc6ff677d0aead7cf2f097c0e7fbb15b49d49d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/309304
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/include/gpu/GrDirectContext.h b/include/gpu/GrDirectContext.h
index 5347878..5d84fcc 100644
--- a/include/gpu/GrDirectContext.h
+++ b/include/gpu/GrDirectContext.h
@@ -88,7 +88,7 @@
 private:
     std::unique_ptr<GrAtlasManager> fAtlasManager;
 
-    // The small path renderer atlas will be stored here
+    std::unique_ptr<GrSmallPathAtlasMgr> fSmallPathAtlasMgr;
 
     typedef GrContext INHERITED;
 };