Extract PrefServiceBase into chrome/browser/api. Use in api and autofill.

chrome/browser/prefs/pref_service.cc

Index: chrome/browser/prefs/pref_service.cc
diff --git a/chrome/browser/prefs/pref_service.cc b/chrome/browser/prefs/pref_service.cc
index 31ad5da8b0a15e8d3a28b08647c789d6bb10490c..612e39f193f42c571fafafefba2eb63e025974a5 100644
--- a/chrome/browser/prefs/pref_service.cc
+++ b/chrome/browser/prefs/pref_service.cc
@@ -27,6 +27,7 @@
 #include "chrome/browser/prefs/pref_model_associator.h"
 #include "chrome/browser/prefs/pref_notifier_impl.h"
 #include "chrome/browser/prefs/pref_value_store.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/prefs/prefs_tab_helper.h"
 #include "chrome/browser/ui/profile_error_dialog.h"
 #include "chrome/common/json_pref_store.h"
@@ -113,6 +114,10 @@ class ReadErrorHandler : public PersistentPrefStore::ReadErrorDelegate {
 
 }  // namespace
 
+PrefServiceBase* PrefServiceBase::ForProfile(Profile* profile) {
+  return profile->GetPrefs();
+}
+
 // static
 PrefService* PrefService::CreatePrefService(
     const FilePath& pref_filename,