Add a new audio extension event OnLevelChanged.

chrome/browser/ui/ash/volume_controller_chromeos.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/ash/volume_controller_chromeos.h"
 
 #include "ash/ash_switches.h"
 #include "ash/audio/sounds.h"
 #include "base/command_line.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 74 matching lines @@
     play_sound = true;
   } else {
     play_sound = audio_handler->GetOutputVolumePercent() != 100;
     audio_handler->AdjustOutputVolumeByPercent(kStepPercentage);
   }
 
   if (play_sound)
     PlayVolumeAdjustSound();
 }
 
-void VolumeController::OnOutputVolumeChanged() {
+void VolumeController::OnOutputNodeVolumeChanged(uint64 node_id,
+                                                 double volume) {
   CrasAudioHandler* audio_handler = CrasAudioHandler::Get();
   extensions::DispatchVolumeChangedEvent(
       audio_handler->GetOutputVolumePercent(),
       audio_handler->IsOutputMuted());
 }
 
 void VolumeController::OnOutputMuteChanged() {
   CrasAudioHandler* audio_handler = CrasAudioHandler::Get();
   extensions::DispatchVolumeChangedEvent(
       audio_handler->GetOutputVolumePercent(),
       audio_handler->IsOutputMuted());
 }