Fix the volume controlling behaviors.

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"
 
 namespace {
 
 // Percent by which the volume should be changed when a volume key is pressed.
 const double kStepPercentage = 4.0;
 
-// Percent to which the volume should be set when the "volume up" key is pressed
-// while we're muted and have the volume set to 0.  See
-// http://crosbug.com/13618.
-const double kVolumePercentOnVolumeUpWhileMuted = 25.0;
-
 }  // namespace
 
 bool VolumeController::HandleVolumeMute(const ui::Accelerator& accelerator) {
   if (accelerator.key_code() == ui::VKEY_F8)
     content::RecordAction(content::UserMetricsAction("Accel_VolumeMute_F8"));
 
   chromeos::AudioHandler* audio_handler = chromeos::AudioHandler::GetInstance();
 
   // Always muting (and not toggling) as per final decision on
   // http://crosbug.com/3751
@@ skipping 19 matching lines @@
   return true;
 }
 
 bool VolumeController::HandleVolumeUp(const ui::Accelerator& accelerator) {
   if (accelerator.key_code() == ui::VKEY_F10)
     content::RecordAction(content::UserMetricsAction("Accel_VolumeUp_F10"));
 
   chromeos::AudioHandler* audio_handler = chromeos::AudioHandler::GetInstance();
   if (audio_handler->IsMuted()) {
     audio_handler->SetMuted(false);
-    if (audio_handler->GetVolumePercent() <= 0.1)  // float comparison
-      audio_handler->SetVolumePercent(kVolumePercentOnVolumeUpWhileMuted);
+    // If volume percent is still 0.0 after reset the mute status, it means that
+    // the mute status was done by VolumeDown, so we need to increase
+    // the volume as usual.
+    if (audio_handler->GetVolumePercent() == 0.0)
+      audio_handler->AdjustVolumeByPercent(kStepPercentage);
   } else {
     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());
 }