Create SkSLOperators, centralize functionality

Change-Id: I3593e7ab0caac2fd572346038cbc8ff63e6fe970
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/366406
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/src/sksl/SkSLMangler.cpp b/src/sksl/SkSLMangler.cpp
index 9c25668..9b6c7fa 100644
--- a/src/sksl/SkSLMangler.cpp
+++ b/src/sksl/SkSLMangler.cpp
@@ -5,7 +5,8 @@
  * found in the LICENSE file.
  */
 
-#include "src/sksl/SkSLMetalCodeGenerator.h"
+#include "src/sksl/SkSLMangler.h"
+#include "src/sksl/ir/SkSLSymbolTable.h"
 
 namespace SkSL {