Remove PrefServiceSimple, replacing it with PrefService and PrefRegistrySimple.

chrome/browser/prefs/chrome_pref_service_factory.cc

Index: chrome/browser/prefs/chrome_pref_service_factory.cc
diff --git a/chrome/browser/prefs/chrome_pref_service_factory.cc b/chrome/browser/prefs/chrome_pref_service_factory.cc
index a074a342930d0583f64aa4a2af936ea3ba6423d7..c0b80c8eeffc4508b4546c69d9245e553f764864 100644
--- a/chrome/browser/prefs/chrome_pref_service_factory.cc
+++ b/chrome/browser/prefs/chrome_pref_service_factory.cc
@@ -14,6 +14,7 @@
 #include "chrome/browser/prefs/command_line_pref_store.h"
 #include "chrome/browser/prefs/pref_model_associator.h"
 #include "chrome/browser/prefs/pref_notifier_impl.h"
+#include "chrome/browser/prefs/pref_registry.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prefs/pref_service_syncable_builder.h"
 #include "chrome/browser/prefs/pref_value_store.h"
@@ -98,11 +99,12 @@ PrefServiceBase* PrefServiceBase::FromBrowserContext(BrowserContext* context) {
 
 namespace chrome_prefs {
 
-PrefServiceSimple* CreateLocalState(
+PrefService* CreateLocalState(
     const FilePath& pref_filename,
     base::SequencedTaskRunner* pref_io_task_runner,
     policy::PolicyService* policy_service,
     PrefStore* extension_prefs,
+    scoped_ptr<PrefRegistry> pref_registry,
     bool async) {

[Mattias Nissler (ping if slow), 2013/01/25 14:57:11]

Maybe we should move the browser_prefs::RegisterLocalState call here?

[Jói, 2013/01/29 16:10:02]

That could be done once the TODO around line 263 of chrome_browser_main.cc (use
a JSONPrefStore instead of an entire PrefService) has been done. Until then,
this would cause an unnecessary call to browser_prefs::RegisterLocalState, which
is pretty expensive.

I've updated the TODO in chrome_browser_main.cc to say this can be fixed once
the TODO is addressed.

   PrefServiceSyncableBuilder builder;
   PrepareBuilder(&builder,
@@ -111,7 +113,7 @@ PrefServiceSimple* CreateLocalState(
                  policy_service,
                  extension_prefs,
                  async);
-  return builder.CreateSimple();
+  return builder.Create(pref_registry.Pass());
 }
 
 PrefServiceSyncable* CreateProfilePrefs(