cps-ir: Support foreign code.

pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart

Index: pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
diff --git a/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart b/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
index 27638c40409bb44c24ab51d8054a0529a0fad51f..90292d857508353730e8a385c7ff7f36924e9837 100644
--- a/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
+++ b/pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart
@@ -862,6 +862,18 @@ class StatementRewriter extends Transformer implements Pass {
   Statement getBranch(If node, bool polarity) {
     return polarity ? node.thenStatement : node.elseStatement;
   }
+
+  @override
+  Expression visitForeignExpression(ForeignExpression node) {
+    _rewriteList(node.arguments);
+    return node;
+  }
+
+  @override
+  Statement visitForeignStatement(ForeignStatement node) {
+    _rewriteList(node.arguments);
+    return node;
+  }
 }
 
 /// Result of combining two expressions, with the potential for reverting the