Add missing copyright headers

diff --git a/pkgs/stream_transform/lib/src/from_handlers.dart b/pkgs/stream_transform/lib/src/from_handlers.dart
index cf1c24d..52ad5b4 100644
--- a/pkgs/stream_transform/lib/src/from_handlers.dart
+++ b/pkgs/stream_transform/lib/src/from_handlers.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2017, 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.
+
 import 'dart:async';
 
 typedef void HandleData<S, T>(S value, EventSink<T> sink);

diff --git a/pkgs/stream_transform/test/from_handlers_test.dart b/pkgs/stream_transform/test/from_handlers_test.dart
index fe9e916..8240b1c 100644
--- a/pkgs/stream_transform/test/from_handlers_test.dart
+++ b/pkgs/stream_transform/test/from_handlers_test.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2017, 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.
+
 import 'dart:async';
 
 import 'package:test/test.dart';

diff --git a/pkgs/stream_transform/test/merge_test.dart b/pkgs/stream_transform/test/merge_test.dart
index 8108b95..75df0e8 100644
--- a/pkgs/stream_transform/test/merge_test.dart
+++ b/pkgs/stream_transform/test/merge_test.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2017, 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.
+
 import 'dart:async';
 
 import 'package:test/test.dart';

diff --git a/pkgs/stream_transform/test/scan_test.dart b/pkgs/stream_transform/test/scan_test.dart
index 717b808..b2b9760 100644
--- a/pkgs/stream_transform/test/scan_test.dart
+++ b/pkgs/stream_transform/test/scan_test.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2017, 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.
+
 import 'dart:async';
 
 import 'package:test/test.dart';

diff --git a/pkgs/stream_transform/test/switch_test.dart b/pkgs/stream_transform/test/switch_test.dart
index 624c1a5..dda658c 100644
--- a/pkgs/stream_transform/test/switch_test.dart
+++ b/pkgs/stream_transform/test/switch_test.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2017, 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.
+
 import 'dart:async';
 
 import 'package:test/test.dart';

diff --git a/pkgs/stream_transform/test/tap_test.dart b/pkgs/stream_transform/test/tap_test.dart
index 1f384ff..f3ef8e3 100644
--- a/pkgs/stream_transform/test/tap_test.dart
+++ b/pkgs/stream_transform/test/tap_test.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2017, 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.
+
 import 'dart:async';
 
 import 'package:test/test.dart';