Remove AudioDeviceObserver and make ADM not inherit from the Module interface.

modules/audio_device/linux/audio_device_alsa_linux.cc

Index: modules/audio_device/linux/audio_device_alsa_linux.cc
diff --git a/modules/audio_device/linux/audio_device_alsa_linux.cc b/modules/audio_device/linux/audio_device_alsa_linux.cc
index f271606dfdac9cc05a71dec3b2957674f5d99a90..bfddf3d8c1ddd237f759bad5619dd3f651a1b528 100644
--- a/modules/audio_device/linux/audio_device_alsa_linux.cc
+++ b/modules/audio_device/linux/audio_device_alsa_linux.cc
@@ -89,11 +89,7 @@ AudioDeviceLinuxALSA::AudioDeviceLinuxALSA() :
     _playIsInitialized(false),
     _AGC(false),
     _recordingDelay(0),
-    _playoutDelay(0),
-    _playWarning(0),
-    _playError(0),
-    _recWarning(0),
-    _recError(0)
+    _playoutDelay(0)
 {
     memset(_oldKeyState, 0, sizeof(_oldKeyState));
     LOG(LS_INFO) << __FUNCTION__ << " created";
@@ -166,10 +162,6 @@ AudioDeviceGeneric::InitStatus AudioDeviceLinuxALSA::Init() {
           << "failed to open X display, typing detection will not work";
     }
 #endif
-    _playWarning = 0;
-    _playError = 0;
-    _recWarning = 0;
-    _recError = 0;
 
     _initialized = true;
 
@@ -1014,8 +1006,6 @@ int32_t AudioDeviceLinuxALSA::InitPlayout()
         _handlePlayout, _playoutFramesIn10MS);
 
     // Init varaibles used for play
-    _playWarning = 0;
-    _playError = 0;
 
     if (_handlePlayout != NULL)
     {
@@ -1447,54 +1437,6 @@ bool AudioDeviceLinuxALSA::Playing() const
     return (_playing);
 }
 
-bool AudioDeviceLinuxALSA::PlayoutWarning() const
-{
-    rtc::CritScope lock(&_critSect);
-    return (_playWarning > 0);
-}
-
-bool AudioDeviceLinuxALSA::PlayoutError() const
-{
-    rtc::CritScope lock(&_critSect);
-    return (_playError > 0);
-}
-
-bool AudioDeviceLinuxALSA::RecordingWarning() const
-{
-    rtc::CritScope lock(&_critSect);
-    return (_recWarning > 0);
-}
-
-bool AudioDeviceLinuxALSA::RecordingError() const
-{
-    rtc::CritScope lock(&_critSect);
-    return (_recError > 0);
-}
-
-void AudioDeviceLinuxALSA::ClearPlayoutWarning()
-{
-    rtc::CritScope lock(&_critSect);
-    _playWarning = 0;
-}
-
-void AudioDeviceLinuxALSA::ClearPlayoutError()
-{
-    rtc::CritScope lock(&_critSect);
-    _playError = 0;
-}
-
-void AudioDeviceLinuxALSA::ClearRecordingWarning()
-{
-    rtc::CritScope lock(&_critSect);
-    _recWarning = 0;
-}
-
-void AudioDeviceLinuxALSA::ClearRecordingError()
-{
-    rtc::CritScope lock(&_critSect);
-    _recError = 0;
-}
-
 // ============================================================================
 //                                 Private Methods
 // ============================================================================