To allow the propagation of under-run in NetEq.

BUG=
R=tina.legrand@webrtc.org, turaj@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1974004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4537 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq4/neteq_impl.cc b/webrtc/modules/audio_coding/neteq4/neteq_impl.cc
index 1d2c4d7..9323b20 100644
--- a/webrtc/modules/audio_coding/neteq4/neteq_impl.cc
+++ b/webrtc/modules/audio_coding/neteq4/neteq_impl.cc
@@ -690,10 +690,9 @@
       samples_from_sync << " samples";
   if (samples_from_sync != output_size_samples_) {
     LOG_F(LS_ERROR) << "samples_from_sync != output_size_samples_";
-    assert(false);
+    // TODO(minyue): treatment of under-run, filling zeros
     memset(output, 0, num_output_samples * sizeof(int16_t));
     *samples_per_channel = output_size_samples_;
-    last_mode_ = kModeError;
     return kSampleUnderrun;
   }
   *samples_per_channel = output_size_samples_;