Make js_ast test line-ending agnostic.

pkg/js_ast/test/printer_callback_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Note: This test relies on LF line endings in the source file.
 
 // Test that JS printer callbacks occur when expected.
 
 library js_ast.printer.callback_test;
 
@@ skipping 87 matching lines @@
   },
 ];
 
 void check(Map<TestMode, String> map) {
   String code = map[TestMode.NONE];
   JavaScriptPrintingOptions options = new JavaScriptPrintingOptions();
   Node node = js.parseForeignJS(code).instantiate({});
   map.forEach((TestMode mode, String expectedOutput) {
     Context context = new Context(mode);
     new Printer(options, context).visit(node);
-    expect(context.getText(), equals(expectedOutput),
+    expect(context.getText(),
+        equals(canonicalizeLineEndings(expectedOutput)),
         reason: "Unexpected output for $code in $mode");
   });
 }
 
+// The string literals may end in \r\n or \n depending on filesystem.
+canonicalizeLineEndings(String s) => s.replaceAll('\r\n', '\n');
+
 class Context extends SimpleJavaScriptPrintingContext {
   final TestMode mode;
   final Map<Node, int> idMap = {};
   final Map<int, List<String>> tagMap = {};
 
   Context(this.mode);
 
   int id(Node node) => idMap.putIfAbsent(node, () => idMap.length);
 
   String tag(int value) => '@$value';
@@ skipping 31 matching lines @@
     if (offset < text.length) {
       sb.write(text.substring(offset));
     }
     return sb.toString();
   }
 }
 
 void main() {
   DATA.forEach(check);
 }