Provide a mechanism for the GCM driver to send message receipts to GCM.

chrome/browser/gcm/fake_gcm_profile_service.h

 // Copyright 2013 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_GCM_FAKE_GCM_PROFILE_SERVICE_H_
 #define CHROME_BROWSER_GCM_FAKE_GCM_PROFILE_SERVICE_H_
 
 #include <list>
 #include <memory>
 #include <vector>
@@ skipping 17 matching lines @@
   // Helper function to be used with
   // KeyedService::SetTestingFactory().
   static std::unique_ptr<KeyedService> Build(content::BrowserContext* context);
 
   explicit FakeGCMProfileService(Profile* profile);
   ~FakeGCMProfileService() override;
 
   void AddExpectedUnregisterResponse(GCMClient::Result result);
 
   void DispatchMessage(const std::string& app_id,
-                       const IncomingMessage& message);
+                       const IncomingMessage& message,
+                       const MessageReceiptCallback& optional_receipt_callback);
 
   const OutgoingMessage& last_sent_message() const {
     return last_sent_message_;
   }
 
   const std::string& last_receiver_id() const {
     return last_receiver_id_;
   }
 
   const std::string& last_registered_app_id() const {
@@ skipping 24 matching lines @@
   std::list<GCMClient::Result> unregister_responses_;
   OutgoingMessage last_sent_message_;
   std::string last_receiver_id_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeGCMProfileService);
 };
 
 }  // namespace gcm
 
 #endif  // CHROME_BROWSER_GCM_FAKE_GCM_PROFILE_SERVICE_H_