Cleanup of SkyBinding, and resultant yak shaving.

sky/sdk/lib/base/hit_test.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:sky' as sky;
+
+abstract class HitTestTarget {
+  void handleEvent(sky.Event event, HitTestEntry entry);
+}
+
+class HitTestEntry {
+  const HitTestEntry(this.target);
+  final HitTestTarget target;
+}
+
+class HitTestResult {
+  final List<HitTestEntry> path = new List<HitTestEntry>();
+  void add(HitTestEntry data) {
+    path.add(data);
+  }
+}