[Sync] Replace uses of ObserverListThreadSafe with WeakHandles

chrome/browser/sync/notifier/non_blocking_invalidation_notifier.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.
 //
 // An implementation of SyncNotifier that wraps InvalidationNotifier
 // on its own thread.
 
 #ifndef CHROME_BROWSER_SYNC_NOTIFIER_NON_BLOCKING_INVALIDATION_NOTIFIER_H_
 #define CHROME_BROWSER_SYNC_NOTIFIER_NON_BLOCKING_INVALIDATION_NOTIFIER_H_
 #pragma once
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
 #include "chrome/browser/sync/notifier/invalidation_version_tracker.h"
 #include "chrome/browser/sync/notifier/sync_notifier.h"
+#include "chrome/browser/sync/notifier/sync_notifier_observer.h"
 #include "chrome/browser/sync/util/weak_handle.h"
 #include "jingle/notifier/base/notifier_options.h"
 
 namespace base {
 class MessageLoopProxy;
 }
 
 namespace sync_notifier {
 
-class NonBlockingInvalidationNotifier : public SyncNotifier {
+class NonBlockingInvalidationNotifier
+    : public SyncNotifier,
+      public SyncNotifierObserver {
  public:
   // |invalidation_version_tracker| must be initialized.
   NonBlockingInvalidationNotifier(
       const notifier::NotifierOptions& notifier_options,
       const InvalidationVersionMap& initial_max_invalidation_versions,
       const browser_sync::WeakHandle<InvalidationVersionTracker>&
           invalidation_version_tracker,
       const std::string& client_info);
 
   virtual ~NonBlockingInvalidationNotifier();
 
   // SyncNotifier implementation.
   virtual void AddObserver(SyncNotifierObserver* observer) OVERRIDE;
   virtual void RemoveObserver(SyncNotifierObserver* observer) OVERRIDE;
   virtual void SetUniqueId(const std::string& unique_id) OVERRIDE;
   virtual void SetState(const std::string& state) OVERRIDE;
   virtual void UpdateCredentials(
       const std::string& email, const std::string& token) OVERRIDE;
   virtual void UpdateEnabledTypes(
       const syncable::ModelTypeSet& enabled_types) OVERRIDE;
   virtual void SendNotification(
       const syncable::ModelTypeSet& changed_types) OVERRIDE;
 
+  // SyncNotifierObserver implementation.
+  virtual void OnIncomingNotification(
+      const syncable::ModelTypePayloadMap& type_payloads) OVERRIDE;
+  virtual void OnNotificationStateChange(bool notifications_enabled) OVERRIDE;
+  virtual void StoreState(const std::string& state) OVERRIDE;
+
  private:
-  // The real guts of NonBlockingInvalidationNotifier, which allows this class
-  // to not be refcounted.
   class Core;
+
+  base::WeakPtrFactory<NonBlockingInvalidationNotifier> weak_ptr_factory_;
+
+  // Our observers (which must live on the parent thread).
+  ObserverList<SyncNotifierObserver> observers_;
+
+  // The real guts of NonBlockingInvalidationNotifier, which allows
+  // this class to live completely on the parent thread.
   scoped_refptr<Core> core_;
   scoped_refptr<base::MessageLoopProxy> parent_message_loop_proxy_;
   scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_;
+
   DISALLOW_COPY_AND_ASSIGN(NonBlockingInvalidationNotifier);
 };
 
 }  // namespace sync_notifier
 
 #endif  // CHROME_BROWSER_SYNC_NOTIFIER_NON_BLOCKING_INVALIDATION_NOTIFIER_H_