Do not display CRAS loopback devices on UI.

ash/system/chromeos/audio/audio_detailed_view.cc

Index: ash/system/chromeos/audio/audio_detailed_view.cc
diff --git a/ash/system/chromeos/audio/audio_detailed_view.cc b/ash/system/chromeos/audio/audio_detailed_view.cc
index 3b023d86fd3711b2d13c42cf733adac7f495e3a4..fa1438b536a8d2809cf0a3f488ce7550e88c6332 100644
--- a/ash/system/chromeos/audio/audio_detailed_view.cc
+++ b/ash/system/chromeos/audio/audio_detailed_view.cc
@@ -118,7 +118,9 @@ void AudioDetailedView::UpdateAudioDevices() {
   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]);