Migrate files to embedder.

samples/android_sample/android_sample.gyp

 # 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.
 
 {
   'conditions': [
     ['OS=="android"',
       {
         'targets': [
           {
             'target_name': 'android_sample',
             'type': 'none',
             'dependencies': [
               '../../runtime/dart-runtime.gyp:android_embedder',
             ],
             'actions': [
               # TODO(gram) - this should have a debug and release version.
               {
                 'action_name': 'build_app',
                 'inputs': [
-                  'jni/*.cc',
-                  'jni/*.h',
                   'assets/dart/*.dart',
                 ],
                 'outputs': [
                   'bin/NativeActivity-debug.apk',
                 ],
                 'action': [ 'ant', 'debug' ]
               }
             ]
           }
         ]
       }
     ]
   ]
 }