components: Move PrefRegistrySyncable into user_prefs namespace.

chrome/browser/content_settings/content_settings_policy_provider.h

Index: chrome/browser/content_settings/content_settings_policy_provider.h
diff --git a/chrome/browser/content_settings/content_settings_policy_provider.h b/chrome/browser/content_settings/content_settings_policy_provider.h
index 2b1580bbb51e5436db68ef47788d6e30273c71d3..a5868204b4ad0e5ff05729094d9ef6ba8705c0c7 100644
--- a/chrome/browser/content_settings/content_settings_policy_provider.h
+++ b/chrome/browser/content_settings/content_settings_policy_provider.h
@@ -16,7 +16,10 @@
 #include "chrome/browser/content_settings/content_settings_origin_identifier_value_map.h"
 
 class PrefService;
+
+namespace user_prefs {
 class PrefRegistrySyncable;
+}
 
 namespace content_settings {
 
@@ -25,7 +28,7 @@ class PolicyProvider : public ObservableProvider {
  public:
   explicit PolicyProvider(PrefService* prefs);
   virtual ~PolicyProvider();
-  static void RegisterUserPrefs(PrefRegistrySyncable* registry);
+  static void RegisterUserPrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // ProviderInterface implementations.
   virtual RuleIterator* GetRuleIterator(