Check in codegen test expectations.

test/codegen/expect/language/scanner_test.js

Index: test/codegen/expect/language/scanner_test.js
diff --git a/test/codegen/expect/language/scanner_test.js b/test/codegen/expect/language/scanner_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..d8503cecf10626e5132e2bfa919b4355a4f3b467
--- /dev/null
+++ b/test/codegen/expect/language/scanner_test.js
@@ -0,0 +1,26 @@
+dart_library.library('language/scanner_test', null, /* Imports */[
+  'dart_sdk'
+], function load__scanner_test(exports, dart_sdk) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const scanner_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  scanner_test.ScannerTest = class ScannerTest extends core.Object {
+    static testMain() {
+      let s = "Hello\tmy\tfriend\n";
+      return s;
+    }
+  };
+  dart.setSignature(scanner_test.ScannerTest, {
+    statics: () => ({testMain: dart.definiteFunctionType(dart.dynamic, [])}),
+    names: ['testMain']
+  });
+  scanner_test.main = function() {
+    scanner_test.ScannerTest.testMain();
+  };
+  dart.fn(scanner_test.main, VoidTodynamic());
+  // Exports:
+  exports.scanner_test = scanner_test;
+});