Remove PrefValueStore's dependency on PrefModelAssociator.

chrome/browser/prefs/pref_value_store.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PREFS_PREF_VALUE_STORE_H_
 #define CHROME_BROWSER_PREFS_PREF_VALUE_STORE_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/prefs/pref_store.h"
 #include "base/values.h"
 
-class PrefModelAssociator;
 class PrefNotifier;
 class PrefStore;
 
 // The PrefValueStore manages various sources of values for Preferences
 // (e.g., configuration policies, extensions, and user settings). It returns
 // the value of a Preference from the source with the highest priority, and
 // allows setting user-defined values for preferences that are not managed.
 //
 // Unless otherwise explicitly noted, all of the methods of this class must
 // be called on the UI thread.
 class PrefValueStore {
  public:
+  typedef base::Callback<void(const std::string&)> PrefChangedCallback;
+
   // In decreasing order of precedence:
   //   |managed_prefs| contains all preferences from mandatory policies.
   //   |extension_prefs| contains preference values set by extensions.
   //   |command_line_prefs| contains preference values set by command-line
   //        switches.
   //   |user_prefs| contains all user-set preference values.
   //   |recommended_prefs| contains all preferences from recommended policies.
   //   |default_prefs| contains application-default preference values. It must
   //        be non-null if any preferences are to be registered.
   //
@@ skipping 11 matching lines @@
   // Creates a clone of this PrefValueStore with PrefStores overwritten
   // by the parameters passed, if unequal NULL.
   PrefValueStore* CloneAndSpecialize(PrefStore* managed_prefs,
                                      PrefStore* extension_prefs,
                                      PrefStore* command_line_prefs,
                                      PrefStore* user_prefs,
                                      PrefStore* recommended_prefs,
                                      PrefStore* default_prefs,
                                      PrefNotifier* pref_notifier);
 
-  // TODO(joi): Remove this completely; the part PrefModelAssociator
-  // needs can be handled simply as a PrefObserver.
-  void set_sync_associator(PrefModelAssociator* sync_associator);
+  // A PrefValueStore can have exactly one callback that is directly
+  // notified of preferences changing in the store. This does not
+  // filter through the PrefNotifier mechanism, which may not forward
+  // certain changes (e.g. unregistered prefs).
+  void set_callback(const PrefChangedCallback& callback);
 
   // Gets the value for the given preference name that has the specified value
   // type. Values stored in a PrefStore that have the matching |name| but
   // a non-matching |type| are silently skipped. Returns true if a valid value
   // was found in any of the available PrefStores. Most callers should use
   // Preference::GetValue() instead of calling this method directly.
   bool GetValue(const std::string& name,
                 base::Value::Type type,
                 const Value** out_value) const;
 
@@ skipping 155 matching lines @@
   PrefStore* GetPrefStore(PrefStoreType type) {
     return pref_stores_[type].store();
   }
   const PrefStore* GetPrefStore(PrefStoreType type) const {
     return pref_stores_[type].store();
   }
 
   // Keeps the PrefStore references in order of precedence.
   PrefStoreKeeper pref_stores_[PREF_STORE_TYPE_MAX + 1];
 
-  // The associator for syncing preferences.
-  PrefModelAssociator* pref_sync_associator_;
+  PrefChangedCallback pref_changed_callback_;
 
-  // Used for generating PREF_CHANGED and PREF_INITIALIZATION_COMPLETED
-  // notifications. This is a weak reference, since the notifier is owned by the
-  // corresponding PrefService.
+  // Used for generating notifications. This is a weak reference,
+  // since the notifier is owned by the corresponding PrefService.
   PrefNotifier* pref_notifier_;
 
   // A mapping of preference names to their registered types.
   PrefTypeMap pref_types_;
 
   // True if not all of the PrefStores were initialized successfully.
   bool initialization_failed_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefValueStore);
 };
 
 #endif  // CHROME_BROWSER_PREFS_PREF_VALUE_STORE_H_