Add support for audio input mute detection on all platforms

media/audio/virtual_audio_input_stream.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/virtual_audio_input_stream.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 155 matching lines @@
 double VirtualAudioInputStream::GetVolume() {
   return 1.0;
 }
 
 void VirtualAudioInputStream::SetAutomaticGainControl(bool enabled) {}
 
 bool VirtualAudioInputStream::GetAutomaticGainControl() {
   return false;
 }
 
+bool VirtualAudioInputStream::IsMuted() {
+  return false;
+}
+
 }  // namespace media