Add support for audio input mute detection on all platforms

media/audio/win/audio_low_latency_input_win.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/win/audio_low_latency_input_win.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/utf_string_conversions.h"
 #include "media/audio/win/audio_manager_win.h"
@@ skipping 235 matching lines @@
 
   // Update the AGC volume level based on the last setting above. Note that,
   // the volume-level resolution is not infinite and it is therefore not
   // possible to assume that the volume provided as input parameter can be
   // used directly. Instead, a new query to the audio hardware is required.
   // This method does nothing if AGC is disabled.
   UpdateAgcVolume();
 }
 
 double WASAPIAudioInputStream::GetVolume() {
-  DLOG_IF(ERROR, !opened_) << "Open() has not been called successfully";
+  DCHECK(opened_) << "Open() has not been called successfully";
   if (!opened_)
     return 0.0;
 
   // Retrieve the current volume level. The value is in the range 0.0 to 1.0.
   float level = 0.0f;
   HRESULT hr = simple_audio_volume_->GetMasterVolume(&level);
   DLOG_IF(WARNING, FAILED(hr)) << "Failed to get input master volume.";
 
   return static_cast<double>(level);
 }
 
+bool WASAPIAudioInputStream::IsMuted() {
+  DCHECK(opened_) << "Open() has not been called successfully";
+  DCHECK(CalledOnValidThread());
+  if (!opened_)
+    return false;
+
+  // Retrieves the current muting state for the audio session.
+  BOOL is_muted = FALSE;
+  HRESULT hr = simple_audio_volume_->GetMute(&is_muted);
+  DLOG_IF(WARNING, FAILED(hr)) << "Failed to get input master volume.";
+
+  return is_muted != FALSE;
+}
+
 // static
 AudioParameters WASAPIAudioInputStream::GetInputStreamParameters(
     const std::string& device_id) {
   int sample_rate = 48000;
   ChannelLayout channel_layout = CHANNEL_LAYOUT_STEREO;
 
   base::win::ScopedCoMem<WAVEFORMATEX> audio_engine_mix_format;
   int effects = AudioParameters::NO_EFFECTS;
   if (SUCCEEDED(GetMixFormat(device_id, &audio_engine_mix_format, &effects))) {
     sample_rate = static_cast<int>(audio_engine_mix_format->nSamplesPerSec);
@@ skipping 464 matching lines @@
     return hr;
 
   // Obtain a reference to the ISimpleAudioVolume interface which enables
   // us to control the master volume level of an audio session.
   hr = audio_client_->GetService(__uuidof(ISimpleAudioVolume),
                                  simple_audio_volume_.ReceiveVoid());
   return hr;
 }
 
 }  // namespace media