[Chromecast] Log sample rate changes and tweak audio logging output.

chromecast/media/cma/backend/alsa/stream_mixer_alsa.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chromecast/media/cma/backend/alsa/stream_mixer_alsa.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <utility>
@@ skipping 329 matching lines @@
                     &unsigned_output_samples_per_second,
                     kAlsaDirDontCare);
   if (requested_rate != unsigned_output_samples_per_second) {
     LOG(ERROR) << "Requested sample rate (" << requested_rate
                << " Hz) does not match the actual sample rate ("
                << unsigned_output_samples_per_second
                << " Hz). This may lead to lower audio quality.";
   }
   output_samples_per_second_ =
       static_cast<int>(unsigned_output_samples_per_second);
+  LOG(INFO) << "Sample rate changed from " << output_samples_per_second_

[kmackay, 2016/01/28 23:25:41]

Seems like this should be moved up above the line where
output_samples_per_second_ is set to the new value.

[jyw, 2016/01/28 23:39:22]

Done.

+            << " to " << unsigned_output_samples_per_second;
 
   snd_pcm_uframes_t requested_buffer_size = alsa_buffer_size_;
   RETURN_ERROR_CODE(PcmHwParamsSetBufferSizeNear, pcm_, pcm_hw_params_,
                     &alsa_buffer_size_);
   if (requested_buffer_size != alsa_buffer_size_) {
     LOG(ERROR) << "Requested buffer size (" << requested_buffer_size
                << " frames) does not match the actual buffer size ("
                << alsa_buffer_size_
                << " frames). This may lead to an increase in "
                   "either audio latency or audio underruns.";
@@ skipping 398 matching lines @@
   rendering_delay_.timestamp_microseconds =
       TimespecToMicroseconds(status_timestamp);
   snd_pcm_sframes_t delay_frames = alsa_->PcmStatusGetDelay(pcm_status_);
   rendering_delay_.delay_microseconds = static_cast<int64_t>(delay_frames) *
                                         base::Time::kMicrosecondsPerSecond /
                                         output_samples_per_second_;
 }
 
 }  // namespace media
 }  // namespace chromecast