Remove Sink and move CollectionSink to async.

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

Index: sdk/lib/_internal/compiler/implementation/compiler.dart
diff --git a/sdk/lib/_internal/compiler/implementation/compiler.dart b/sdk/lib/_internal/compiler/implementation/compiler.dart
index 01e5cc2813090a642cd612efb2c75984d6a7839b..23d8c8a3dc70f9c4e7deec238a9b9d3e9c8ec96f 100644
--- a/sdk/lib/_internal/compiler/implementation/compiler.dart
+++ b/sdk/lib/_internal/compiler/implementation/compiler.dart
@@ -1108,13 +1108,15 @@ bool invariant(Spannable spannable, var condition, {String message: null}) {
 }
 
 /// A sink that drains into /dev/null.
-class NullSink extends Sink<String> {
+class NullSink extends StreamSink<String> {
   final String name;
 
   NullSink(this.name);
 
   add(String value) {}
 
+  void signalError(AsyncError error) {}

[Lasse Reichstein Nielsen, 2013/02/04 13:21:10]

Consider throwing the error.

[ahe, 2013/02/04 15:27:30]

The error should be thrown. You should *never* ignore an error.

But what is this AsyncError business about? Where I have seen it in use, it
gives horrible stack traces, so I think it is a misfeature.

Also, I don't understand what this method is doing here. I'm looking for a
simple interface that lets me abstract a string buffer or a stream, but I'm
beginning to doubt that sinks fit the bill. I should probably stop using this
interface altogether. I don't understand why I would ever tell a StringBuffer or
a Stream that an error occurred, so this is not making any sense to me at all.

+
   void close() {}
 
   toString() => name;