sync: move invalidation version prefs out of SyncPrefs into InvalidatorStorage.

sync/notifier/non_blocking_invalidation_notifier.cc

 // 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.
 
 #include "sync/notifier/non_blocking_invalidation_notifier.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/threading/thread.h"
 #include "sync/notifier/invalidation_notifier.h"
 
 namespace sync_notifier {
 
 class NonBlockingInvalidationNotifier::Core
     : public base::RefCountedThreadSafe<NonBlockingInvalidationNotifier::Core>,
+      // SyncNotifierObserver to observe the InvalidationNotifier we create.
       public SyncNotifierObserver {
  public:
   // Called on parent thread.  |delegate_observer| should be
   // initialized.
   explicit Core(
       const browser_sync::WeakHandle<SyncNotifierObserver>&
           delegate_observer);
 
   // Helpers called on I/O thread.
   void Initialize(
       const notifier::NotifierOptions& notifier_options,
       const InvalidationVersionMap& initial_max_invalidation_versions,
       const browser_sync::WeakHandle<InvalidationStateTracker>&
           invalidation_state_tracker,
       const std::string& client_info);
   void Teardown();
   void SetUniqueId(const std::string& unique_id);
   void SetState(const std::string& state);
   void UpdateCredentials(const std::string& email, const std::string& token);
   void UpdateEnabledTypes(syncable::ModelTypeSet enabled_types);
 
-  // SyncNotifierObserver implementation (all called on I/O thread).
+  // SyncNotifierObserver implementation (all called on I/O thread by
+  // InvalidationNotifier).
   virtual void OnIncomingNotification(
       const syncable::ModelTypePayloadMap& type_payloads,
       IncomingNotificationSource source);
   virtual void OnNotificationStateChange(bool notifications_enabled);
   virtual void StoreState(const std::string& state);
 
  private:
   friend class
       base::RefCountedThreadSafe<NonBlockingInvalidationNotifier::Core>;
   // Called on parent or I/O thread.
@@ skipping 210 matching lines @@
 }
 
 void NonBlockingInvalidationNotifier::StoreState(
     const std::string& state) {
   DCHECK(parent_message_loop_proxy_->BelongsToCurrentThread());
   FOR_EACH_OBSERVER(SyncNotifierObserver, observers_,
                     StoreState(state));
 }
 
 }  // namespace sync_notifier