move SkTPin to include/private

Change-Id: Ib0dc823d331a7cddc5da1d1be83136ce803a7871
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/327783
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Reed <reed@google.com>
diff --git a/src/effects/SkTrimPathEffect.cpp b/src/effects/SkTrimPathEffect.cpp
index bb7a99e..7c91491 100644
--- a/src/effects/SkTrimPathEffect.cpp
+++ b/src/effects/SkTrimPathEffect.cpp
@@ -7,6 +7,7 @@
 
 #include "include/core/SkPathMeasure.h"
 #include "include/effects/SkTrimPathEffect.h"
+#include "include/private/SkTPin.h"
 #include "src/core/SkReadBuffer.h"
 #include "src/core/SkWriteBuffer.h"
 #include "src/effects/SkTrimPE.h"