Add UMA logging for target audio bitrate

webrtc/modules/audio_coding/main/acm2/codec_owner_unittest.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 82 matching lines @@
   // Verify NoEncoding.
   expected_timestamp += 2 * kDataLengthSamples;
   {
     SCOPED_TRACE("Fourth encoding");
     EncodeAndVerify(0, expected_timestamp, kCngPt, 1);
   }
 }
 
 TEST_F(CodecOwnerTest, ExternalEncoder) {
   MockAudioEncoderMutable external_encoder;
+  EXPECT_CALL(external_encoder, GetTargetBitrate())
+      .WillRepeatedly(Return(-1));  // Flag adaptive bitrate (doesn't matter).
   codec_owner_.SetEncoders(&external_encoder, -1, VADNormal, -1);
   const int kSampleRateHz = 8000;
   const int kPacketSizeSamples = kSampleRateHz / 100;
   int16_t audio[kPacketSizeSamples] = {0};
   uint8_t encoded[kPacketSizeSamples];
   AudioEncoder::EncodedInfo info;
   EXPECT_CALL(external_encoder, SampleRateHz())
       .WillRepeatedly(Return(kSampleRateHz));
 
   {
@@ skipping 28 matching lines @@
   // Change back to external encoder again.
   codec_owner_.SetEncoders(&external_encoder, -1, VADNormal, -1);
   info = codec_owner_.Encoder()->Encode(2, audio, arraysize(audio),
                                         arraysize(encoded), encoded);
   EXPECT_EQ(2u, info.encoded_timestamp);
   external_encoder.Reset();  // Dummy call to mark the sequence of expectations.
 }
 
 }  // namespace acm2
 }  // namespace webrtc