Fix dartc tests and pub after IOSink change.

samples/build_dart/build.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 build_dart;
 
 import "dart:io";
 import "package:args/args.dart";
 
 bool cleanBuild;
@@ skipping 100 matching lines @@
 void _processFile(String arg) {
   if (arg.endsWith(".foo")) {
     print("processing: ${arg}");
 
     File file = new File(arg);
 
     String contents = file.readAsStringSync();
 
     File outFile = new File("${arg}bar");
 
-    IOSink<File> out = outFile.openWrite();
+    IOSink out = outFile.openWrite();
     out.writeln("// processed from ${file.path}:");
     if (contents != null) {
       out.write(contents);
     }
     out.close();
 
     _findErrors(arg);
 
     print("wrote: ${outFile.path}");
   }
@@ skipping 16 matching lines @@
 }
 
 /**
  * If this file is a generated file (based on the extension), delete it.
  */
 void _maybeClean(File file) {
   if (file.path.endsWith(".foobar")) {
     file.delete();
   }
 }