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

chrome/browser/chromeos/audio/audio_mixer_alsa.cc

Index: chrome/browser/chromeos/audio/audio_mixer_alsa.cc
diff --git a/chrome/browser/chromeos/audio/audio_mixer_alsa.cc b/chrome/browser/chromeos/audio/audio_mixer_alsa.cc
index c51cca8554cc0660791fb6a2041afdb495341b57..464a4a01f4898bda9e6e82ddf6f1b27ac5703e34 100644
--- a/chrome/browser/chromeos/audio/audio_mixer_alsa.cc
+++ b/chrome/browser/chromeos/audio/audio_mixer_alsa.cc
@@ -41,6 +41,9 @@ const char* const kMasterElementNames[] = {
 };
 const char kPCMElementName[] = "PCM";
 
+const char kMicElementName[] = "Mic";
+const char kFrontMicElementName[] = "Front Mic";
+
 // Default minimum and maximum volume (before we've loaded the actual range from
 // ALSA), in decibels.
 const double kDefaultMinVolumeDb = -90.0;
@@ -76,6 +79,8 @@ AudioMixerAlsa::AudioMixerAlsa()
       initial_volume_percent_(kDefaultVolumePercent),
       alsa_mixer_(NULL),
       pcm_element_(NULL),
+      mic_element_(NULL),
+      front_mic_element_(NULL),
       disconnected_event_(true, false),
       num_connection_attempts_(0) {
 }
@@ -127,9 +132,7 @@ void AudioMixerAlsa::SetVolumePercent(double percent) {
     initial_volume_percent_ = percent;
   } else {
     volume_db_ = PercentToDb(percent);
-    if (!apply_is_pending_)
-      thread_->message_loop()->PostTask(FROM_HERE,
-          base::Bind(&AudioMixerAlsa::ApplyState, base::Unretained(this)));
+    ApplyStateIfNeeded();
   }
 }
 
@@ -138,13 +141,53 @@ bool AudioMixerAlsa::IsMuted() {
   return is_muted_;
 }
 
-void AudioMixerAlsa::SetMuted(bool muted) {
+void AudioMixerAlsa::SetMuted(bool mute) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   base::AutoLock lock(lock_);
-  is_muted_ = muted;
-  if (!apply_is_pending_)
-    thread_->message_loop()->PostTask(FROM_HERE,
-        base::Bind(&AudioMixerAlsa::ApplyState, base::Unretained(this)));
+  if (is_mute_locked_) {
+    NOTREACHED() << "Capture mute has been locked!";
+    return;
+  }
+  is_muted_ = mute;
+  ApplyStateIfNeeded();
+}
+
+bool AudioMixerAlsa::IsMuteLocked() {
+  base::AutoLock lock(lock_);
+  return is_mute_locked_;
+}
+
+void AudioMixerAlsa::SetMuteLocked(bool locked) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  base::AutoLock lock(lock_);
+  is_mute_locked_ = locked;
+}
+
+bool AudioMixerAlsa::IsCaptureMuted() {
+  base::AutoLock lock(lock_);
+  return is_capture_muted_;
+}
+
+void AudioMixerAlsa::SetCaptureMuted(bool mute) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  base::AutoLock lock(lock_);
+  if (is_capture_mute_locked_) {
+    NOTREACHED() << "Capture mute has been locked!";
+    return;
+  }
+  is_capture_muted_ = mute;
+  ApplyStateIfNeeded();
+}
+
+bool AudioMixerAlsa::IsCaptureMuteLocked() {
+  base::AutoLock lock(lock_);
+  return is_capture_mute_locked_;
+}
+
+void AudioMixerAlsa::SetCaptureMuteLocked(bool locked) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  base::AutoLock lock(lock_);
+  is_capture_mute_locked_ = locked;
 }
 
 void AudioMixerAlsa::Connect() {
@@ -266,11 +309,17 @@ bool AudioMixerAlsa::ConnectInternal() {
 
   VLOG(1) << "Volume range is " << min_volume_db << " dB to "
           << max_volume_db << " dB";
+
+  snd_mixer_elem_t* mic_element = FindElementWithName(handle, kMicElementName);
+  snd_mixer_elem_t* front_mic_element =
+      FindElementWithName(handle, kFrontMicElementName);
   {
     base::AutoLock lock(lock_);
     alsa_mixer_ = handle;
     master_element_ = master_element;
     pcm_element_ = pcm_element;
+    mic_element_ = mic_element;
+    front_mic_element_ = front_mic_element;
     min_volume_db_ = min_volume_db;
     max_volume_db_ = max_volume_db;
     volume_db_ = PercentToDb(initial_volume_percent_);
@@ -301,10 +350,12 @@ void AudioMixerAlsa::ApplyState() {
     return;
 
   bool should_mute = false;
+  bool should_mute_capture = false;
   double new_volume_db = 0;
   {
     base::AutoLock lock(lock_);
     should_mute = is_muted_;
+    should_mute_capture = is_capture_muted_;
     new_volume_db = should_mute ? min_volume_db_ : volume_db_;
     apply_is_pending_ = false;
   }
@@ -325,6 +376,10 @@ void AudioMixerAlsa::ApplyState() {
   }
 
   SetElementMuted(master_element_, should_mute);
+  if (mic_element_)
+    SetElementMuted(mic_element_, should_mute_capture);
+  if (front_mic_element_)
+    SetElementMuted(front_mic_element_, should_mute_capture);
 }
 
 snd_mixer_elem_t* AudioMixerAlsa::FindElementWithName(
@@ -440,4 +495,13 @@ double AudioMixerAlsa::PercentToDb(double percent) const {
       (max_volume_db_ - min_volume_db_) + min_volume_db_;
 }
 
+void AudioMixerAlsa::ApplyStateIfNeeded() {
+  lock_.AssertAcquired();
+  if (!apply_is_pending_) {
+    thread_->message_loop()->PostTask(
+        FROM_HERE,
+        base::Bind(&AudioMixerAlsa::ApplyState, base::Unretained(this)));
+  }
+}
+
 }  // namespace chromeos