Plumb invalidations from Tango to the extensions code for the Push Messaging API.

chrome/browser/extensions/api/push_messaging/invalidation_handler_observer.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_EXTENSIONS_API_PUSH_MESSAGING_INVALIDATION_HANDLER_OBSERVER_H_
-#define CHROME_BROWSER_EXTENSIONS_API_PUSH_MESSAGING_INVALIDATION_HANDLER_OBSERVER_H_
-
-#include <string>
-
-namespace extensions {
-
-// Observer interface for the push messaging invalidation handler. For each
-// object that was invalidated, OnMessage() will be called back once for that
-// object.
-class InvalidationHandlerObserver {
- public:
-  virtual ~InvalidationHandlerObserver() {}
-  virtual void OnMessage(const std::string& extension_id,
-                         int subchannel,
-                         const std::string& payload) = 0;
-};
-
-}  // namespace extensions
-
-#endif  // CHROME_BROWSER_EXTENSIONS_API_PUSH_MESSAGING_INVALIDATION_HANDLER_OBSERVER_H_