NetEq: Add new method last_output_sample_rate_hz

webrtc/modules/audio_coding/neteq/tools/neteq_external_decoder_test.cc

 /*
  *  Copyright (c) 2015 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 38 matching lines @@
   int num_channels;
   EXPECT_EQ(NetEq::kOK,
             neteq_->GetAudio(max_length,
                              output,
                              &samples_per_channel,
                              &num_channels,
                              output_type));
   EXPECT_EQ(channels_, num_channels);
   EXPECT_EQ(static_cast<size_t>(kOutputLengthMs * sample_rate_hz_ / 1000),
             samples_per_channel);
+  EXPECT_EQ(sample_rate_hz_, neteq_->last_output_sample_rate_hz());
   return samples_per_channel;
 }
 
 }  // namespace test
 }  // namespace webrtc