Remove TODO referring to issue1981, which I just marked WontFix.

webrtc/modules/audio_processing/test/audio_processing_unittest.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 2730 matching lines @@
                     std::tr1::make_tuple(16000, 44100, 32000, 44100, 15, 15),
                     std::tr1::make_tuple(16000, 44100, 16000, 44100, 15, 15),
                     std::tr1::make_tuple(16000, 32000, 48000, 32000, 25, 35),
                     std::tr1::make_tuple(16000, 32000, 32000, 32000, 25, 0),
                     std::tr1::make_tuple(16000, 32000, 16000, 32000, 25, 20),
                     std::tr1::make_tuple(16000, 16000, 48000, 16000, 35, 20),
                     std::tr1::make_tuple(16000, 16000, 32000, 16000, 40, 20),
                     std::tr1::make_tuple(16000, 16000, 16000, 16000, 0, 0)));
 #endif
 
-// TODO(henrike): re-implement functionality lost when removing the old main
-//                function. See
-//                https://code.google.com/p/webrtc/issues/detail?id=1981
-
 }  // namespace
 }  // namespace webrtc