Remove transformEvents and make StreamEventTransformer extend StreamTransformer.

tests/lib/async/stream_controller_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.
 
 // Test the basic StreamController and StreamController.singleSubscription.
 library stream_controller_test;
 
 import 'dart:async';
 import 'event_helper.dart';
 
@@ skipping 75 matching lines @@
   }));
   sentEvents.replay(c);
   Expect.listEquals(expectedEvents.events, actualEvents.events);
 
   // Test transform.
   c = new StreamController.broadcast();
   sentEvents = new Events()..add("a")..error(42)..add("b")..close();
   expectedEvents =
       new Events()..error("a")..add(42)..error("b")..add("foo")..close();
   actualEvents = new Events.capture(c.stream.transform(
-      new StreamTransformer.from(
-          onData: (v, s) { s.signalError(new AsyncError(v)); },
-          onError: (e, s) { s.add(e.error); },
-          onDone: (s) {
+      new StreamTransformer(
+          handleData: (v, s) { s.signalError(new AsyncError(v)); },
+          handleError: (e, s) { s.add(e.error); },
+          handleDone: (s) {
             s.add("foo");
             s.close();
           })));
   sentEvents.replay(c);
   Expect.listEquals(expectedEvents.events, actualEvents.events);
 
   // Test multiple filters.
   c = new StreamController.broadcast();
   sentEvents = new Events()..add(42)
                            ..add("snugglefluffy")
@@ skipping 165 matching lines @@
     });
     sentEvents.replay(c);
   }
 
   // Test transform.
   c = new StreamController();
   sentEvents = new Events()..add("a")..error(42)..add("b")..close();
   expectedEvents =
       new Events()..error("a")..add(42)..error("b")..add("foo")..close();
   actualEvents = new Events.capture(c.stream.transform(
-      new StreamTransformer.from(
-          onData: (v, s) { s.signalError(new AsyncError(v)); },
-          onError: (e, s) { s.add(e.error); },
-          onDone: (s) {
+      new StreamTransformer(
+          handleData: (v, s) { s.signalError(new AsyncError(v)); },
+          handleError: (e, s) { s.add(e.error); },
+          handleDone: (s) {
             s.add("foo");
             s.close();
           })));
   sentEvents.replay(c);
   Expect.listEquals(expectedEvents.events, actualEvents.events);
 
   // Test multiple filters.
   c = new StreamController();
   sentEvents = new Events()..add(42)
                            ..add("snugglefluffy")
@@ skipping 91 matching lines @@
   actualEvents = new Events.capture(c.stream.distinct((a, b) => a < b));
   sentEvents.replay(c);
   Expect.listEquals(expectedEvents.events, actualEvents.events);
 }
 
 main() {
   testMultiController();
   testSingleController();
   testExtraMethods();
 }