Introduce per-tab preferences service.

chrome/browser/prefs/pref_notifier_impl.h

Index: chrome/browser/prefs/pref_notifier_impl.h
diff --git a/chrome/browser/prefs/pref_notifier_impl.h b/chrome/browser/prefs/pref_notifier_impl.h
index b16ad1144fa02f0701cf2c5377c6fe4be433200a..416fd3b89dbb0582fe126a424d3eeaebe89c4d6e 100644
--- a/chrome/browser/prefs/pref_notifier_impl.h
+++ b/chrome/browser/prefs/pref_notifier_impl.h
@@ -13,6 +13,7 @@
 #include "base/threading/non_thread_safe.h"
 #include "chrome/browser/prefs/pref_notifier.h"
 
+class PrefModelAssociator;
 class PrefService;
 
 namespace content {
@@ -23,9 +24,12 @@ class NotificationObserver;
 class PrefNotifierImpl : public PrefNotifier,
                          public base::NonThreadSafe {
  public:
-  explicit PrefNotifierImpl(PrefService* pref_service);
+  PrefNotifierImpl();
   virtual ~PrefNotifierImpl();
 
+  void SetPrefModelAssociator(PrefModelAssociator* associator);
+  void SetPrefService(PrefService* pref_service);
+
   // If the pref at the given path changes, we call the observer's Observe
   // method with PREF_CHANGED.
   void AddPrefObserver(const char* path, content::NotificationObserver* obs);
@@ -53,6 +57,8 @@ class PrefNotifierImpl : public PrefNotifier,
   // Weak reference; the notifier is owned by the PrefService.
   PrefService* pref_service_;
 
+  PrefModelAssociator* pref_model_associator_;
+
   PrefObserverMap pref_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefNotifierImpl);