Fork some more files from the old framework, so that the transition will be easier to perform.

sky/sdk/lib/animation/generators.dart

Index: sky/sdk/lib/animation/generators.dart
diff --git a/sky/sdk/lib/framework/animation/generators.dart b/sky/sdk/lib/animation/generators.dart
similarity index 97%
copy from sky/sdk/lib/framework/animation/generators.dart
copy to sky/sdk/lib/animation/generators.dart
index 253692bd862f4a40ddb0fb57bc59df0404526fff..2110ed0b9aaeca209210ac1c9fb48ab18cc7cb6d 100644
--- a/sky/sdk/lib/framework/animation/generators.dart
+++ b/sky/sdk/lib/animation/generators.dart
@@ -2,14 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import '../../app/scheduler.dart' as scheduler;
-import 'curves.dart';
 import 'dart:async';
 import 'dart:math' as math;
+
+import '../app/scheduler.dart' as scheduler;
+import 'curves.dart';
 import 'mechanics.dart';
 
 abstract class Generator {
-  Stream<double> get onTick; // TODO(ianh): rename this to tickStream once we've landed the fn2 fork
+  Stream<double> get onTick; // TODO(ianh): rename this to tickStream
   void cancel();
 }