Do not display CRAS loopback devices on UI.

ash/system/chromeos/audio/audio_detailed_view.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/system/chromeos/audio/audio_detailed_view.h"
 
 #include "ash/system/tray/fixed_sized_scroll_view.h"
 #include "ash/system/tray/hover_highlight_view.h"
 #include "ash/system/tray/tray_constants.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 100 matching lines @@
 }
 
 void AudioDetailedView::UpdateAudioDevices() {
   output_devices_.clear();
   input_devices_.clear();
   chromeos::AudioDeviceList devices;
   CrasAudioHandler::Get()->GetAudioDevices(&devices);
   for (size_t i = 0; i < devices.size(); ++i) {
     // Don't display keyboard mic or aokr type.
     if (devices[i].type == chromeos::AUDIO_TYPE_KEYBOARD_MIC ||
-        devices[i].type == chromeos::AUDIO_TYPE_AOKR)
+        devices[i].type == chromeos::AUDIO_TYPE_AOKR ||
+        devices[i].type == chromeos::AUDIO_TYPE_POST_MIX_LOOPBACK ||
+        devices[i].type == chromeos::AUDIO_TYPE_POST_DSP_LOOPBACK)
       continue;
     if (devices[i].is_input)
       input_devices_.push_back(devices[i]);
     else
       output_devices_.push_back(devices[i]);
   }
   UpdateScrollableList();
 }
 
 void AudioDetailedView::UpdateScrollableList() {
@@ skipping 33 matching lines @@
     AudioDeviceMap::iterator iter = device_map_.find(sender);
     if (iter == device_map_.end())
       return;
     chromeos::AudioDevice& device = iter->second;
     CrasAudioHandler::Get()->SwitchToDevice(device, true);
   }
 }
 
 }  // namespace tray
 }  // namespace ash