Revert "Revert "moved SkSL ExpressionStatement's data into IRNode""

This reverts commit dd33b3ea9063458be8758e9d0dd564f128107ede.

Change-Id: I348b2b5976966a7451d88bd7f96ce17ce1702b79
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/320826
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
diff --git a/src/sksl/SkSLMetalCodeGenerator.cpp b/src/sksl/SkSLMetalCodeGenerator.cpp
index 8cd36f1..a169144 100644
--- a/src/sksl/SkSLMetalCodeGenerator.cpp
+++ b/src/sksl/SkSLMetalCodeGenerator.cpp
@@ -1249,7 +1249,7 @@
             this->writeBlock(s.as<Block>());
             break;
         case Statement::Kind::kExpression:
-            this->writeExpression(*s.as<ExpressionStatement>().fExpression, kTopLevel_Precedence);
+            this->writeExpression(*s.as<ExpressionStatement>().expression(), kTopLevel_Precedence);
             this->write(";");
             break;
         case Statement::Kind::kReturn:
@@ -1796,7 +1796,7 @@
             return result;
         }
         case Statement::Kind::kExpression:
-            return this->requirements(s->as<ExpressionStatement>().fExpression.get());
+            return this->requirements(s->as<ExpressionStatement>().expression().get());
         case Statement::Kind::kReturn: {
             const ReturnStatement& r = s->as<ReturnStatement>();
             return this->requirements(r.fExpression.get());