components: Extract pref_registry component out of user_prefs.

components/user_prefs/pref_registry_syncable.h

Index: components/user_prefs/pref_registry_syncable.h
diff --git a/components/user_prefs/pref_registry_syncable.h b/components/user_prefs/pref_registry_syncable.h
index 64de0a332e45a0182c1dc1a73e1865331d746b1a..f213cefb168024ce135ca35c1def994163361378 100644
--- a/components/user_prefs/pref_registry_syncable.h
+++ b/components/user_prefs/pref_registry_syncable.h
@@ -10,7 +10,7 @@
 
 #include "base/callback.h"
 #include "base/prefs/pref_registry.h"
-#include "components/user_prefs/user_prefs_export.h"
+#include "components/user_prefs/pref_registry_export.h"
 
 namespace base {
 class DictionaryValue;
@@ -31,7 +31,7 @@ namespace user_prefs {
 // appropriate time before the PrefService for these preferences is
 // constructed. See e.g. chrome/browser/prefs/browser_prefs.cc which
 // does this for Chrome.
-class USER_PREFS_EXPORT PrefRegistrySyncable : public PrefRegistry {
+class PREF_REGISTRY_EXPORT PrefRegistrySyncable : public PrefRegistry {
  public:
   // Enum used when registering preferences to determine if it should
   // be synced or not. Syncable priority preferences are preferences that are