Flip the left/right speaker when the device is in yoga mode.

chromeos/audio/cras_audio_handler.cc

 // Copyright (c) 2013 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 "chromeos/audio/cras_audio_handler.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/bind.h"
@@ skipping 235 matching lines @@
 }
 
 void CrasAudioHandler::RemoveAllActiveNodes() {
   for (AudioDeviceMap::const_iterator it = audio_devices_.begin();
        it != audio_devices_.end();
        ++it) {
     RemoveActiveNodeInternal(it->second.id);
   }
 }
 
+void CrasAudioHandler::SwapLeftRight(bool swap) {
+  if (!active_output_node_id_) {
+    VLOG(1) << "SwapLeftRight: Cannot find primary active output node";
+    return;
+  }
+
+  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->SwapLeftRight(
+      active_output_node_id_, swap);

[flackr, 2014/10/01 20:32:33]

We shouldn't swap the channels on any device except for the internal speakers:
https://code.google.com/p/chromium/codesearch#chromium/src/chromeos/audio/aud...

[jennyz, 2014/10/01 20:41:19]

Cras decides if the channel swapping is supported, for the current code, as I
can see, only the internal speaker supports this feature. cychiang@, please
correct me if I am wrong.

[jennyz, 2014/10/01 20:52:11]

Think again, you are right, we'd only guard to make this only applies to
internal speaker, will upload another patch soon, Thank!

[jennyz, 2014/10/01 21:30:33]

Done.

+}
+
 bool CrasAudioHandler::has_alternative_input() const {
   return has_alternative_input_;
 }
 
 bool CrasAudioHandler::has_alternative_output() const {
   return has_alternative_output_;
 }
 
 void CrasAudioHandler::SetOutputVolumePercent(int volume_percent) {
   // Set all active devices to the same volume.
@@ skipping 579 matching lines @@
     if (node_id == active_output_node_id_)
       active_output_node_id_ = 0;
     chromeos::DBusThreadManager::Get()
         ->GetCrasAudioClient()
         ->RemoveActiveOutputNode(node_id);
   }
   FOR_EACH_OBSERVER(AudioObserver, observers_, OnActiveOutputNodeChanged());
 }
 
 }  // namespace chromeos