Remove PrefServiceSimple, replacing it with PrefService and PrefRegistrySimple.

chrome/browser/extensions/app_launcher.h

Index: chrome/browser/extensions/app_launcher.h
diff --git a/chrome/browser/extensions/app_launcher.h b/chrome/browser/extensions/app_launcher.h
index 8a4b062d9fe77ae9a05e2aec694610adf10a24d6..b9eda5679c417ff2f087a5a5f408e10f778f678a 100644
--- a/chrome/browser/extensions/app_launcher.h
+++ b/chrome/browser/extensions/app_launcher.h
@@ -8,7 +8,7 @@
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 
-class PrefServiceSimple;
+class PrefRegistrySimple;
 
 namespace extensions {
 
@@ -26,7 +26,7 @@ void UpdateIsAppLauncherEnabled(
 bool IsAppLauncherEnabled();
 
 namespace app_launcher {
-void RegisterPrefs(PrefServiceSimple* pref_service);
+void RegisterPrefs(PrefRegistrySimple* pref_service);
 }
 
 }  // namespace extensions