Remove transformEvents and make StreamEventTransformer extend StreamTransformer.

tests/lib/async/stream_event_transform_test.dart

 // Copyright (c) 2011, 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 stream_event_transform_test;
 
 import 'dart:async';
 import '../../../pkg/unittest/lib/unittest.dart';
 import 'event_helper.dart';
 
@@ skipping 12 matching lines @@
 void handleDone(StreamSink<int> sink) {
   sink.add(99);
   sink.close();
 }
 
 class EventTransformer extends StreamEventTransformer<int,int> {
   void handleData(int data, StreamSink<int> sink) {
     sink.signalError(new AsyncError("$data"));
     sink.add(data + 1);
   }
+
   void handleError(AsyncError e, StreamSink<int> sink) {
     String value = e.error;
     int data = int.parse(value);
     sink.add(data);
     sink.signalError(new AsyncError("${data + 1}"));
   }
 
   void handleDone(StreamSink<int> sink) {
     sink.add(99);
     sink.close();
   }
 }
 
 main() {
   {
     StreamController c = new StreamController();
     Events expected = new Events()..error("0")..add(1)
                                   ..error("1")..add(2)
                                   ..add(3)..error("4")
                                   ..add(99)..close();
     Events input = new Events()..add(0)..add(1)..error("3")..close();
     Events actual = new Events.capture(
-        c.stream.transformEvents(new EventTransformer()));
+        c.stream.transform(new EventTransformer()));
     actual.onDone(() {
       Expect.listEquals(expected.events, actual.events);
     });
     input.replay(c);
   }
 
   {
     StreamController c = new StreamController();
     Events expected = new Events()..error("0")..add(1)
                                   ..error("1")..add(2)
                                   ..add(3)..error("4")
                                   ..add(99)..close();
     Events input = new Events()..add(0)..add(1)..error("3")..close();
     Events actual = new Events.capture(
-        c.stream.transformEvents(new StreamEventTransformer.from(
+        c.stream.transform(new StreamTransformer(
             handleData: handleData,
             handleError: handleError,
             handleDone: handleDone
         )));
     actual.onDone(() {
       Expect.listEquals(expected.events, actual.events);
     });
     input.replay(c);
   }
 }