Mute ALSA audio completely

chrome/browser/chromeos/audio_mixer_alsa.h

Index: chrome/browser/chromeos/audio_mixer_alsa.h
diff --git a/chrome/browser/chromeos/audio_mixer_alsa.h b/chrome/browser/chromeos/audio_mixer_alsa.h
index eeb5b26b104f3cb46a0af154c06445350233309b..69c05e02e039b43f9822f020a956d9c681ded833 100644
--- a/chrome/browser/chromeos/audio_mixer_alsa.h
+++ b/chrome/browser/chromeos/audio_mixer_alsa.h
@@ -81,6 +81,10 @@ class AudioMixerAlsa : public AudioMixer {
   bool GetElementMuted_Locked(_snd_mixer_elem* elem) const;
   void SetElementMuted_Locked(_snd_mixer_elem* elem, bool mute);
 
+  // Verify PCM can be opened, which also instantiates the PCM mixer element
+  // which is needed for finer volume control and for muting by setting to zero.
+  void PingPCM();

[Daniel Erat, 2011/03/02 17:45:07]

worthwhile to return a bool here?

[davejcool, 2011/03/03 20:05:02]

I thought about returning bool here as well, but Andrew suggested just in-lining
it... which I'm also fine with since it's not called from anywhere else, and is
very similar to the other code in that area.

+
   // Volume range limits are computed once during InitializeAlsaMixer.
   double min_volume_;
   double max_volume_;