Refactor preference syncing.

chrome/browser/chromeos/audio_mixer_alsa.cc

Index: chrome/browser/chromeos/audio_mixer_alsa.cc
diff --git a/chrome/browser/chromeos/audio_mixer_alsa.cc b/chrome/browser/chromeos/audio_mixer_alsa.cc
index 1bb3edcb8f9fedeb7d4a04722b6c2f4f3adc5615..e5597cdb35d860d98731f99578c0d479f4966675 100644
--- a/chrome/browser/chromeos/audio_mixer_alsa.cc
+++ b/chrome/browser/chromeos/audio_mixer_alsa.cc
@@ -198,9 +198,13 @@ AudioMixer::State AudioMixerAlsa::GetState() const {
 // static
 void AudioMixerAlsa::RegisterPrefs(PrefService* local_state) {
   if (!local_state->FindPreference(prefs::kAudioVolume))
-    local_state->RegisterDoublePref(prefs::kAudioVolume, kPrefVolumeInvalid);
+    local_state->RegisterDoublePref(prefs::kAudioVolume,
+                                    kPrefVolumeInvalid,
+                                    false /* don't sync pref */);
   if (!local_state->FindPreference(prefs::kAudioMute))
-    local_state->RegisterIntegerPref(prefs::kAudioMute, kPrefMuteInvalid);
+    local_state->RegisterIntegerPref(prefs::kAudioMute,
+                                     kPrefMuteInvalid,
+                                     false /* don't sync pref */);
 }
 
 ////////////////////////////////////////////////////////////////////////////////