Implement two new policies to control muting the audio I/O.

chrome/browser/chromeos/audio/audio_mixer.h

Index: chrome/browser/chromeos/audio/audio_mixer.h
diff --git a/chrome/browser/chromeos/audio/audio_mixer.h b/chrome/browser/chromeos/audio/audio_mixer.h
index cb9dd67d951fbdb144392b99fdea37a3508220d0..62cf29f7e3b3ebb98375d8d8657986063dad81f9 100644
--- a/chrome/browser/chromeos/audio/audio_mixer.h
+++ b/chrome/browser/chromeos/audio/audio_mixer.h
@@ -29,9 +29,34 @@ class AudioMixer {
   // Is the device currently muted?
   virtual bool IsMuted() = 0;
 
-  // Mutes or unmutes the device, possibly asynchronously.
+  // Mutes or unmutes the device, possibly asynchronously.  The caller must
+  // first verify that the mute state is not locked by calling IsMuteLocked.
+  // If SetMuteLocked has been called with true this function will not change

[Daniel Erat, 2012/08/29 17:35:10]

nit: remove the "If SetMuteLocked has been called..." sentence, since it implies
that calling this function after SetMuteLocked(true) is valid (when it'll
actually trigger a NOTREACHED(), which i believe crashes in debug builds)

[pastarmovj, 2012/08/31 07:28:24]

Done.

+  // the mute state until it is unlocked with another call to
+  // SetMuteLocked(false).
   virtual void SetMuted(bool mute) = 0;
 
+  // Is the device's mute state currently locked?
+  virtual bool IsMuteLocked() = 0;
+
+  // Locks the mute state of the device to whatever state it currently is in.
+  // Call SetMuteLocked with false to allow changing the mute state again.
+  virtual void SetMuteLocked(bool locked) = 0;
+
+  // Is the capture device currently muted?
+  virtual bool IsCaptureMuted() = 0;
+
+  // Mutes or unmutes the capture device, possible asynchronously.  The caller
+  // must first verify that the mute state is not locked by calling
+  // IsCaptureMuteLocked.
+  virtual void SetCaptureMuted(bool mute) = 0;
+
+  // Is the capture device's mute state currently locked?
+  virtual bool IsCaptureMuteLocked() = 0;
+
+  // Locks the capture mute state of the device.
+  virtual void SetCaptureMuteLocked(bool locked) = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioMixer);
 };