Fix the volume controlling behaviors.

chrome/browser/chromeos/audio/audio_handler.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/chromeos/audio/audio_handler.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/logging.h"
@@ skipping 22 matching lines @@
 const int kPrefMuteOff = 0;
 const int kPrefMuteOn = 1;
 
 static AudioHandler* g_audio_handler = NULL;
 
 }  // namespace
 
 // static
 void AudioHandler::Initialize() {
   CHECK(!g_audio_handler);
-  g_audio_handler = new AudioHandler();
+#if defined(USE_CRAS)
+  g_audio_handler = new AudioHandler(new AudioMixerCras());
+#else
+  g_audio_handler = new AudioHandler(new AudioMixerAlsa());
+#endif
 }
 
 // static
 void AudioHandler::Shutdown() {
   // We may call Shutdown without calling Initialize, e.g. if we exit early.
   if (g_audio_handler) {
     delete g_audio_handler;
     g_audio_handler = NULL;
   }
 }
 
 // static
+void AudioHandler::InitializeForTesting(AudioMixer* mixer) {
+  CHECK(!g_audio_handler);
+  g_audio_handler = new AudioHandler(mixer);
+}
+
+// static
 AudioHandler* AudioHandler::GetInstance() {
   VLOG_IF(1, !g_audio_handler)
       << "AudioHandler::GetInstance() called with NULL global instance.";
   return g_audio_handler;
 }
 
 // static
 void AudioHandler::RegisterPrefs(PrefService* local_state) {
   if (!local_state->FindPreference(prefs::kAudioVolumePercent))
     local_state->RegisterDoublePref(prefs::kAudioVolumePercent,
@@ skipping 40 matching lines @@
 }
 
 void AudioHandler::AddVolumeObserver(VolumeObserver* observer) {
   volume_observers_.AddObserver(observer);
 }
 
 void AudioHandler::RemoveVolumeObserver(VolumeObserver* observer) {
   volume_observers_.RemoveObserver(observer);
 }
 
-AudioHandler::AudioHandler()
-#if defined(USE_CRAS)
-    : mixer_(new AudioMixerCras()),
-#else
-    : mixer_(new AudioMixerAlsa()),
-#endif
+AudioHandler::AudioHandler(AudioMixer* mixer)
+    : mixer_(mixer),
       prefs_(g_browser_process->local_state()) {
   mixer_->SetVolumePercent(prefs_->GetDouble(prefs::kAudioVolumePercent));
   mixer_->SetMuted(prefs_->GetInteger(prefs::kAudioMute) == kPrefMuteOn);
   mixer_->Init();
 }
 
 AudioHandler::~AudioHandler() {
   mixer_.reset();
 };
 
 }  // namespace chromeos