Modify the volume visuals:

chrome/browser/ui/views/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/views/ash/volume_controller_chromeos.h"
 
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/audio/audio_handler.h"
 #include "chrome/browser/extensions/system/system_api.h"
 #include "content/public/browser/user_metrics.h"
@@ skipping 53 matching lines @@
     audio_handler->AdjustVolumeByPercent(kStepPercentage);
   }
 
   extensions::DispatchVolumeChangedEvent(audio_handler->GetVolumePercent(),
                                          audio_handler->IsMuted());
   return true;
 }
 
 void VolumeController::SetVolumePercent(double percent) {
   chromeos::AudioHandler* audio_handler = chromeos::AudioHandler::GetInstance();
-  if (audio_handler->IsMuted()) {
-    audio_handler->SetMuted(false);
-  }
   audio_handler->SetVolumePercent(percent);
   extensions::DispatchVolumeChangedEvent(audio_handler->GetVolumePercent(),
                                          audio_handler->IsMuted());
 }