Add support for audio input mute detection on all platforms

media/audio/cras/cras_input.cc

 // Copyright (c) 2012 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 "media/audio/cras/cras_input.h"
 
 #include <math.h>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
@@ skipping 283 matching lines @@
 }
 
 double CrasInputStream::GetVolume() {
   if (!client_)
     return 0.0;
 
   long dB = cras_client_get_system_capture_gain(client_) / 100.0;
   return GetVolumeRatioFromDecibels(dB);
 }
 
+bool CrasInputStream::IsMuted() {
+  return false;
+}
+
 double CrasInputStream::GetVolumeRatioFromDecibels(double dB) const {
   return pow(10, dB / 20.0);
 }
 
 double CrasInputStream::GetDecibelsFromVolumeRatio(double volume_ratio) const {
   return 20 * log10(volume_ratio);
 }
 
 }  // namespace media