header self-sufficiency and idempotency

Change-Id: I4ec74a358e11d85c6eaf1658efd6f1391ee5e387
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/223930
Commit-Queue: Hal Canary <halcanary@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Auto-Submit: Hal Canary <halcanary@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
diff --git a/src/gpu/geometry/GrRect.h b/src/gpu/geometry/GrRect.h
index ffded09..9a0bee7 100644
--- a/src/gpu/geometry/GrRect.h
+++ b/src/gpu/geometry/GrRect.h
@@ -8,6 +8,7 @@
 #ifndef GrRect_DEFINED
 #define GrRect_DEFINED
 
+#include "include/core/SkMatrix.h"
 #include "include/core/SkRect.h"
 #include "include/core/SkTypes.h"
 #include "include/private/SkTo.h"