Migrate EliminateUnreachableCode into Transform.

Change-Id: Ib32895a78a8de4c49ce1208f0c1b9b111d092b42
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/456643
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
diff --git a/src/sksl/transform/SkSLBuiltinVariableScanner.cpp b/src/sksl/transform/SkSLBuiltinVariableScanner.cpp
index 463848f..7b57d91 100644
--- a/src/sksl/transform/SkSLBuiltinVariableScanner.cpp
+++ b/src/sksl/transform/SkSLBuiltinVariableScanner.cpp
@@ -7,6 +7,7 @@
 
 #include "src/sksl/transform/SkSLTransform.h"
 
+#include "include/private/SkSLProgramKind.h"
 #include "src/sksl/SkSLCompiler.h"
 #include "src/sksl/SkSLContext.h"
 #include "src/sksl/SkSLIntrinsicMap.h"