Remove PrefServiceSimple, replacing it with PrefService and PrefRegistrySimple.

chrome/browser/chromeos/audio/audio_handler.cc

Index: chrome/browser/chromeos/audio/audio_handler.cc
diff --git a/chrome/browser/chromeos/audio/audio_handler.cc b/chrome/browser/chromeos/audio/audio_handler.cc
index 6d3da0dfb15ca791db39a3a5cbed76b2b7992b17..fe3a7236ab9f08c839b748aab688a06ae91e7141 100644
--- a/chrome/browser/chromeos/audio/audio_handler.cc
+++ b/chrome/browser/chromeos/audio/audio_handler.cc
@@ -15,6 +15,7 @@
 #else
 #include "chrome/browser/chromeos/audio/audio_mixer_alsa.h"
 #endif
+#include "chrome/browser/prefs/pref_registrar_simple.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/pref_names.h"
@@ -78,27 +79,18 @@ AudioHandler* AudioHandler::GetInstance() {
 }
 
 // static
-void AudioHandler::RegisterPrefs(PrefServiceSimple* local_state) {
-  if (!local_state->FindPreference(prefs::kAudioVolumePercent)) {
-    local_state->RegisterDoublePref(prefs::kAudioVolumePercent,
-                                    kDefaultVolumePercent);
-  }
-  if (!local_state->FindPreference(prefs::kAudioMute)) {
-    local_state->RegisterIntegerPref(prefs::kAudioMute,
-                                     kPrefMuteOff);
-  }
-
-  if (!local_state->FindPreference(prefs::kAudioOutputAllowed)) {
-    // Register the prefs backing the audio muting policies.
-    local_state->RegisterBooleanPref(prefs::kAudioOutputAllowed,
-                                     true);
-  }
+void AudioHandler::RegisterPrefs(PrefRegistrarSimple* local_state) {
+  local_state->RegisterDoublePref(prefs::kAudioVolumePercent,
+                                  kDefaultVolumePercent);
+  local_state->RegisterIntegerPref(prefs::kAudioMute,
+                                   kPrefMuteOff);
+  // Register the prefs backing the audio muting policies.
+  local_state->RegisterBooleanPref(prefs::kAudioOutputAllowed,
+                                   true);
   // This pref has moved to the media subsystem but we should verify it is there
   // before we use it.
-  if (!local_state->FindPreference(prefs::kAudioCaptureAllowed)) {
-    local_state->RegisterBooleanPref(prefs::kAudioCaptureAllowed,
-                                     true);
-  }
+  local_state->RegisterBooleanPref(prefs::kAudioCaptureAllowed,
+                                   true);
 }
 
 double AudioHandler::GetVolumePercent() {