Add support for audio input mute detection on all platforms.

TBR=rkc@chromium.org
BUG=422275
TEST=Manual tests using DVLOGs to confirm valid microphone mute states.

Review URL: https://codereview.chromium.org/645923002

Cr-Commit-Position: refs/heads/master@{#299891}

4 files changed, 30 insertions, 0 deletions

diff --git a/media/audio/mac/audio_input_mac.cc b/media/audio/mac/audio_input_mac.cc
index b7f6e17..af5d9bc 100644
--- a/media/audio/mac/audio_input_mac.cc
+++ b/media/audio/mac/audio_input_mac.cc
@@ -136,6 +136,11 @@ double PCMQueueInAudioInputStream::GetVolume() {
   return 0.0;
 }
 
+bool PCMQueueInAudioInputStream::IsMuted() {
+  NOTREACHED() << "Only supported for low-latency mode.";
+  return false;
+}
+
 void PCMQueueInAudioInputStream::SetAutomaticGainControl(bool enabled) {
   NOTREACHED() << "Only supported for low-latency mode.";
 }
diff --git a/media/audio/mac/audio_input_mac.h b/media/audio/mac/audio_input_mac.h
index 37afcee..6c1b4a14f 100644
--- a/media/audio/mac/audio_input_mac.h
+++ b/media/audio/mac/audio_input_mac.h
@@ -38,6 +38,7 @@ class PCMQueueInAudioInputStream : public AudioInputStream {
   virtual double GetVolume() override;
   virtual void SetAutomaticGainControl(bool enabled) override;
   virtual bool GetAutomaticGainControl() override;
+  virtual bool IsMuted() override;
 
  private:
   // Issue the OnError to |callback_|;
diff --git a/media/audio/mac/audio_low_latency_input_mac.cc b/media/audio/mac/audio_low_latency_input_mac.cc
index 1baa09f..2b2ce00 100644
--- a/media/audio/mac/audio_low_latency_input_mac.cc
+++ b/media/audio/mac/audio_low_latency_input_mac.cc
@@ -451,6 +451,29 @@ double AUAudioInputStream::GetVolume() {
   return 0.0;
 }
 
+bool AUAudioInputStream::IsMuted() {
+  // Verify that we have a valid device.
+  DCHECK_NE(input_device_id_, kAudioObjectUnknown) << "Device ID is unknown";
+
+  AudioObjectPropertyAddress property_address = {
+    kAudioDevicePropertyMute,
+    kAudioDevicePropertyScopeInput,
+    kAudioObjectPropertyElementMaster
+  };
+
+  if (!AudioObjectHasProperty(input_device_id_, &property_address)) {
+    DLOG(ERROR) << "Device does not support checking master mute state";
+    return false;
+  }
+
+  UInt32 muted = 0;
+  UInt32 size = sizeof(muted);
+  OSStatus result = AudioObjectGetPropertyData(
+      input_device_id_, &property_address, 0, NULL, &size, &muted);
+  DLOG_IF(WARNING, result != noErr) << "Failed to get mute state";
+  return result == noErr && muted != 0;
+}
+
 // AUHAL AudioDeviceOutput unit callback
 OSStatus AUAudioInputStream::InputProc(void* user_data,
                                        AudioUnitRenderActionFlags* flags,
diff --git a/media/audio/mac/audio_low_latency_input_mac.h b/media/audio/mac/audio_low_latency_input_mac.h
index 623cf1d..b3950ffd 100644
--- a/media/audio/mac/audio_low_latency_input_mac.h
+++ b/media/audio/mac/audio_low_latency_input_mac.h
@@ -72,6 +72,7 @@ class AUAudioInputStream : public AgcAudioStream<AudioInputStream> {
   virtual double GetMaxVolume() override;
   virtual void SetVolume(double volume) override;
   virtual double GetVolume() override;
+  virtual bool IsMuted() override;
 
   // Returns the current hardware sample rate for the default input device.
   MEDIA_EXPORT static int HardwareSampleRate();