Use package:sky imports consistently

sky/sdk/lib/rendering/object.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 'dart:math' as math;
 import 'dart:sky' as sky;
 import 'dart:sky' show Point, Offset, Size, Rect, Color, Paint, Path;
 
-import '../base/debug.dart';
-import '../base/hit_test.dart';
-import '../base/node.dart';
-import '../base/scheduler.dart' as scheduler;
+import 'package:sky/base/debug.dart';
+import 'package:sky/base/hit_test.dart';
+import 'package:sky/base/node.dart';
+import 'package:sky/base/scheduler.dart' as scheduler;
 
 export 'dart:sky' show Point, Offset, Size, Rect, Color, Paint, Path;
-export '../base/hit_test.dart' show HitTestTarget, HitTestEntry, HitTestResult;
-
+export 'package:sky/base/hit_test.dart' show HitTestTarget, HitTestEntry, HitTestResult;
 
 class ParentData {
   void detach() {
     detachSiblings();
   }
   void detachSiblings() { } // workaround for lack of inter-class mixins in Dart
   void merge(ParentData other) {
     // override this in subclasses to merge in data from other into this
     assert(other.runtimeType == this.runtimeType);
   }
@@ skipping 673 matching lines @@
     int count = 1;
     ChildType child = _firstChild;
     while (child != null) {
       result += '${prefix}child ${count}: ${child.toString(prefix)}';
       count += 1;
       child = child.parentData.nextSibling;
     }
     return result;
   }
 }