Move leap to lib/compiler/samples.

samples/leap/request_cache.dart

-// 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.
-
-#library('request_cache');
-
-#import('dart:html');
-
-/** File system implementation using HTML5's Web Storage. */
-class HttpRequestCache {
-  final Storage storage;
-
-  HttpRequestCache() : storage = window.sessionStorage;
-
-  String readAll(String filename) {
-    String response = storage[filename];
-
-    if (response == null) {
-      HttpRequest xr = new HttpRequest();
-      xr.open("GET", filename, false);
-      xr.send();
-      response = xr.responseText;
-      storage[filename] = response;
-    }
-    return response;
-  }
-}