Make package: work like Dart expects in preparation for a Sky SDK

sky/tests/resources/event-sender.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import "/sky/framework/embedder.dart";
 import "dart:async";
 import "dart:sky";
 import "dart:sky.internals" as internals;
 import "package:mojo/services/input_events/public/interfaces/input_event_constants.mojom.dart" as constants;
 import "package:mojo/services/input_events/public/interfaces/input_events.mojom.dart" as events;
 import "package:mojo/services/input_events/public/interfaces/input_key_codes.mojom.dart" as codes;
+import "package:sky/framework/embedder.dart";
 import "package:sky/services/testing/test_harness.mojom.dart" as harness;
 
 bool _isDone = false;
 int _keyPressesRemaining = 0;
 
 final Set<int> _chars = new Set.from([
   codes.KeyboardCode_A,
   codes.KeyboardCode_B,
   codes.KeyboardCode_C,
   codes.KeyboardCode_D,
@@ skipping 78 matching lines @@
                      ..unmodifiedText = keyCode));
   }
 }
 
 void done() {
   if (_isDone)
     throw "Already done.";
   _isDone = true;
   _checkComplete();
 }