ServiceWorker: Add a function to abort all pending jobs in SWJobCoordinator

content/browser/service_worker/service_worker_register_job_base.h

 // Copyright 2014 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 CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_REGISTER_JOB_BASE_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_REGISTER_JOB_BASE_H_
 
 namespace content {
 
 // A base class for ServiceWorkerRegisterJob and ServiceWorkerUnregisterJob. A
 // job lives only for the lifetime of a single registration or unregistration.
 class ServiceWorkerRegisterJobBase {
  public:
   enum RegistrationJobType { REGISTRATION, UNREGISTRATION, };
 
   virtual ~ServiceWorkerRegisterJobBase() {}
 
   // Starts the job. This method should be called once and only once per job.
   virtual void Start() = 0;
 
+  // Aborts the job. This method should be called once and only once per job.
+  virtual void Abort() = 0;
+
   // Returns true if this job is identical to |job| for the purpose of
   // collapsing them together in a ServiceWorkerJobCoordinator queue.
   // Registration jobs are equal if they are for the same pattern and script
   // URL; unregistration jobs are equal if they are for the same pattern.
   virtual bool Equals(ServiceWorkerRegisterJobBase* job) = 0;
 
   // Returns the type of this job.
   virtual RegistrationJobType GetType() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_REGISTER_JOB_BASE_H_