Introduce per-tab preferences service.

chrome/browser/prefs/pref_service.h

 // Copyright (c) 2011 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.
 
 // This provides a way to access the application's current preferences.
 
 #ifndef CHROME_BROWSER_PREFS_PREF_SERVICE_H_
 #define CHROME_BROWSER_PREFS_PREF_SERVICE_H_
 #pragma once
 
@@ skipping 128 matching lines @@
   static PrefService* CreatePrefService(const FilePath& pref_filename,
                                         PrefStore* extension_pref_store,
                                         bool async);
 
   // Creates an incognito copy of the pref service that shares most pref stores
   // but uses a fresh non-persistent overlay for the user pref store and an
   // individual extension pref store (to cache the effective extension prefs for
   // incognito windows).
   PrefService* CreateIncognitoPrefService(PrefStore* incognito_extension_prefs);
 
+  // Creates a per-tab copy of the pref service that shares most pref stores
+  // and allows WebKit-related preferences to be overridden on per-tab basis.
+  PrefService* CreatePrefServiceWithPerTabPrefStore();
+
   virtual ~PrefService();
 
   // Reloads the data from file. This should only be called when the importer
   // is running during first run, and the main process may not change pref
   // values while the importer process is running. Returns true on success.
   bool ReloadPersistentPrefs();
 
   // Returns true if the preference for the given preference name is available
   // and is managed.
   bool IsManagedPreference(const char* pref_name) const;
@@ skipping 131 matching lines @@
   // preference is not registered.
   const Preference* FindPreference(const char* pref_name) const;
 
   bool ReadOnly() const;
 
   // SyncableService getter.
   // TODO(zea): Have PrefService implement SyncableService directly.
   SyncableService* GetSyncableService();
 
  protected:
-  // Construct a new pref service, specifying the pref sources as explicit
-  // PrefStore pointers. This constructor is what CreatePrefService() ends up
-  // calling. It's also used for unit tests.
-  PrefService(PrefStore* managed_platform_prefs,
-              PrefStore* managed_cloud_prefs,
-              PrefStore* extension_prefs,
-              PrefStore* command_line_prefs,
-              PersistentPrefStore* user_prefs,
-              PrefStore* recommended_platform_prefs,
-              PrefStore* recommended_cloud_prefs,
-              DefaultPrefStore* default_store,
+  // Construct a new pref service. This constructor is what
+  // CreateXXXPrefService() end up calling.  It's also used for unit tests.
+  PrefService(PrefValueStore* pref_value_store,
               bool async);
 
-  // The PrefNotifier handles registering and notifying preference observers.
-  // It is created and owned by this PrefService. Subclasses may access it for
-  // unit testing.
-  scoped_ptr<PrefNotifierImpl> pref_notifier_;
-
  private:
   class PreferencePathComparator {
    public:
     bool operator() (Preference* lhs, Preference* rhs) const {
       return lhs->name() < rhs->name();
     }
   };
   typedef std::set<Preference*, PreferencePathComparator> PreferenceSet;
 
   friend class PrefServiceMockBuilder;
@@ skipping 51 matching lines @@
   // |type| may only be Values::TYPE_DICTIONARY or Values::TYPE_LIST and
   // |path| must point to a registered preference of type |type|.
   // Ownership of the returned value remains at the user pref store.
   base::Value* GetMutableUserPref(const char* path,
                                   base::Value::Type type);
 
   // The PrefValueStore provides prioritized preference values. It is created
   // and owned by this PrefService. Subclasses may access it for unit testing.
   scoped_ptr<PrefValueStore> pref_value_store_;
 
+  // The PrefNotifier handles registering and notifying preference observers.
+  // It is created and owned by this PrefService.
+  scoped_ptr<PrefNotifierImpl> pref_notifier_;
+
   // Pref Stores and profile that we passed to the PrefValueStore.
   scoped_refptr<PersistentPrefStore> user_pref_store_;
   scoped_refptr<DefaultPrefStore> default_store_;
 
   // Local cache of registered Preference objects. The default_store_
   // is authoritative with respect to what the types and default values
   // of registered preferences are.
   mutable PreferenceSet prefs_;
 
   // The model associator that maintains the links with the sync db.
   scoped_ptr<PrefModelAssociator> pref_sync_associator_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefService);
 };
 
 #endif  // CHROME_BROWSER_PREFS_PREF_SERVICE_H_