Move frog/leg to lib/compiler/implementation.

frog/leg/lib/clock.dart

Index: frog/leg/lib/clock.dart
===================================================================
--- frog/leg/lib/clock.dart	(revision 5925)
+++ frog/leg/lib/clock.dart	(working copy)
@@ -1,20 +0,0 @@
-// Copyright (c) 2012, 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.
-
-/**
- * The class [Clock] provides access to a monotonically incrementing clock
- * device.
- */
-class Clock {
-
-  /**
-   * Returns the current clock tick.
-   */
-  static int now() => Primitives.dateNow();
-
-  /**
-   * Returns the frequency of clock ticks in Hz.
-   */
-  static int frequency() => 1000;
-}