Work around for HDMI audio output rediscovering transistion loss.

ash/system/chromeos/audio/tray_audio_delegate_chromeos.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/tray_audio_delegate_chromeos.h"
 
 #include "chromeos/audio/cras_audio_handler.h"
 #include "grit/ash_resources.h"
 
 using chromeos::CrasAudioHandler;
@@ skipping 48 matching lines @@
 void TrayAudioDelegateChromeOs::SetOutputVolumeLevel(int level) {
   CrasAudioHandler::Get()->SetOutputVolumePercent(level);
 }
 
 void TrayAudioDelegateChromeOs::SetInternalSpeakerChannelMode(
     AudioChannelMode mode) {
   CrasAudioHandler::Get()->SwapInternalSpeakerLeftRightChannel(
       mode == LEFT_RIGHT_SWAPPED);
 }
 
+void TrayAudioDelegateChromeOs::SetActiveHDMIOutoutRediscoveringIfNecessary(
+    bool force_rediscovering) {
+  CrasAudioHandler::Get()->SetActiveHDMIOutoutRediscoveringIfNecessary(
+      force_rediscovering);
+}
+
 }  // namespace system
 }  // namespace ash