Merge IO v2 branch to bleeding edge

sdk/lib/_internal/compiler/implementation/dart2js.dart

 // Copyright (c) 2012, 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.
 
 library dart2js;
 
 import 'dart:async';
 import 'dart:collection' show Queue, LinkedHashMap;
 import 'dart:io';
 import 'dart:uri';
@@ skipping 272 matching lines @@
       } else {
         fail('Error: Unknown extension: $extension');
       }
     } else {
       uri = out.resolve('$name.$extension');
     }
 
     if (uri.scheme != 'file') {
       fail('Error: Unhandled scheme ${uri.scheme} in $uri.');
     }
-    var outputStream = new File(uriPathToNative(uri.path)).openOutputStream();
+    IOSink output =
+        new File(uriPathToNative(uri.path)).openWrite();
 
     CountingSink sink;
 
     onDone() {
       if (sourceMapFileName != null) {
         String sourceMapTag = '//@ sourceMappingURL=$sourceMapFileName\n';
         sink.count += sourceMapTag.length;
-        outputStream.writeString(sourceMapTag);
+        output.addString(sourceMapTag);
       }
-      outputStream.close();
+      output.close();
       if (isPrimaryOutput) {
         charactersWritten += sink.count;
       }
     }
 
     var controller = new StreamController<String>();
-    controller.stream.listen(outputStream.writeString, onDone: onDone);
+    controller.stream.listen(output.addString, onDone: onDone);
     sink = new CountingSink(controller);
     return sink;
   }
 
   api.compile(uri, libraryRoot, packageRoot,
               inputProvider.readStringFromUri, handler,
               options, outputProvider)
       .then(compilationDone);
 }
 
@@ skipping 179 matching lines @@
     } catch (ignored) {
       print('Internal error: error while printing exception');
     }
     try {
       print(trace);
     } finally {
       exit(253); // 253 is recognized as a crash by our test scripts.
     }
   }
 }