Turn audio ducking on by default on Windows again.

content/renderer/media/media_stream_audio_processor_options.cc

 // Copyright 2013 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 "content/renderer/media/media_stream_audio_processor_options.h"
 
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
@@ skipping 44 matching lines @@
   // Enable the extended filter mode AEC on all non-mobile platforms.
   { MediaAudioConstraints::kGoogExperimentalEchoCancellation, true },
 #endif
   { MediaAudioConstraints::kGoogAutoGainControl, true },
   { MediaAudioConstraints::kGoogExperimentalAutoGainControl, true },
   { MediaAudioConstraints::kGoogNoiseSuppression, true },
   { MediaAudioConstraints::kGoogHighpassFilter, true },
   { MediaAudioConstraints::kGoogTypingNoiseDetection, true },
   { MediaAudioConstraints::kGoogExperimentalNoiseSuppression, false },
 #if defined(OS_WIN)
-  // TODO(tommi): Turn this back to |true| on Windows when ducking issues
-  // have been resolved.
-  // Bugs: crbug/391414, crbug/391247.
-  { kMediaStreamAudioDucking, false },
+  { kMediaStreamAudioDucking, true },
 #else
   { kMediaStreamAudioDucking, false },
 #endif
 };
 
 bool IsAudioProcessingConstraint(const std::string& key) {
   // |kMediaStreamAudioDucking| does not require audio processing.
   return key != kMediaStreamAudioDucking;
 }
 
@@ skipping 247 matching lines @@
   }
 
   int median = 0, std = 0;
   if (!audio_processing->echo_cancellation()->GetDelayMetrics(&median, &std)) {
     stats->echo_delay_median_ms = median;
     stats->echo_delay_std_ms = std;
   }
 }
 
 }  // namespace content