Generate cached_patches.dart using new Dartium swtich

tools/dartium/generate_app/generate_cached_patches.dart

 // Copyright (c) 2013, 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.
 
-import "dart:js" as js;
-
 void main() {
   try {
-    var cached_files = js.createCachedPatchesFile();
-    print("$cached_files");
+    print("Generated Patches");
   } catch (e) {
     var workedElem = document.querySelector("#worked");
     var failedElem = document.querySelector("#failed");
     workedElem.style.dispay = 'none';
     failedElem.style.visibility = 'inline';
   }
 }