components: Move PrefRegistrySyncable into user_prefs namespace.

chrome/browser/prefs/pref_service_syncable_builder.h

Index: chrome/browser/prefs/pref_service_syncable_builder.h
diff --git a/chrome/browser/prefs/pref_service_syncable_builder.h b/chrome/browser/prefs/pref_service_syncable_builder.h
index 9b15c92c655be28399abf06a2796426a1bfc406c..df0e53d0a7bf289c042ee37894b4f4f7279966b6 100644
--- a/chrome/browser/prefs/pref_service_syncable_builder.h
+++ b/chrome/browser/prefs/pref_service_syncable_builder.h
@@ -8,13 +8,16 @@
 #include "base/prefs/pref_service_builder.h"
 
 class CommandLine;
-class PrefRegistrySyncable;
 class PrefServiceSyncable;
 
 namespace policy {
 class PolicyService;
 }
 
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
 // A PrefServiceBuilder that also knows how to build a
 // PrefServiceSyncable, and may know about Chrome concepts such as
 // PolicyService.
@@ -34,7 +37,8 @@ class PrefServiceSyncableBuilder : public PrefServiceBuilder {
   // Specifies to use an actual command-line backed command-line pref store.
   PrefServiceSyncableBuilder& WithCommandLine(CommandLine* command_line);
 
-  virtual PrefServiceSyncable* CreateSyncable(PrefRegistrySyncable* registry);
+  virtual PrefServiceSyncable* CreateSyncable(
+      user_prefs::PrefRegistrySyncable* registry);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PrefServiceSyncableBuilder);