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

webrtc/modules/audio_processing/test/audio_processing_unittest.cc

Index: webrtc/modules/audio_processing/test/audio_processing_unittest.cc
diff --git a/webrtc/modules/audio_processing/test/audio_processing_unittest.cc b/webrtc/modules/audio_processing/test/audio_processing_unittest.cc
index 809fd3b87e2dbf1f2981a704997b7cb30b8b3740..eac165c542d8d69d246e40ee6c73b2482e8464dd 100644
--- a/webrtc/modules/audio_processing/test/audio_processing_unittest.cc
+++ b/webrtc/modules/audio_processing/test/audio_processing_unittest.cc
@@ -2748,9 +2748,5 @@ INSTANTIATE_TEST_CASE_P(
                     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