Cleanup references to the old DDC repo

pkg/dev_compiler/lib/src/compiler/module_builder.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.
 
 import 'package:args/args.dart' show ArgParser, ArgResults;
 import 'package:path/path.dart' as path;
 
 import '../js_ast/js_ast.dart';
 import 'js_names.dart';
 
@@ skipping 220 matching lines @@
         var names = export.exportedNames;
         // export * is not emitted by the compiler, so we don't handle it here.
         assert(names != null);
         for (var name in names) {
           statements
               .add(js.statement('#.# = #;', [exportsVar, name.name, name]));
         }
       }
     }
 
-    // TODO(vsm): See https://github.com/dart-lang/dev_compiler/issues/512
+    // TODO(vsm): See https://github.com/dart-lang/sdk/issues/27309
     // This extra level of indirection should be unnecessary.
     var block =
         js.statement("(function() { 'use strict'; #; })()", [statements]);
 
     return new Program([block]);
   }
 }
 
 /// Generates AMD modules (used in browsers with RequireJS).
 class AmdModuleBuilder extends _ModuleBuilder {
@@ skipping 82 matching lines @@
   // Ensure the identifier first character is not numeric and that the whole
   // identifier is not a keyword.
   if (result.startsWith(new RegExp('[0-9]')) || invalidVariableName(result)) {
     return '\$$result';
   }
   return result;
 }
 
 // Invalid characters for identifiers, which would need to be escaped.
 final _invalidCharInIdentifier = new RegExp(r'[^A-Za-z_$0-9]');