[Blink-WebWorkers] WorkerSharedTimer cancels extra delayed tasks.

public/platform/WebThread.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
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  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 #ifndef WebThread_h
 #define WebThread_h
 
 #include "WebCommon.h"
+#include "base/memory/weak_ptr.h"

[jochen (gone - plz use gerrit), 2014/09/12 14:11:54]

you can't use base from blink, there is wtf/WeakPtr.h

however, i don't think you need a weak pointer here at all

 
 namespace blink {
 
 // Provides an interface to an embedder-defined thread implementation.
 //
 // Deleting the thread blocks until all pending, non-delayed tasks have been
 // run.
 class BLINK_PLATFORM_EXPORT WebThread {
 public:
     class Task {
     public:
         virtual ~Task() { }
         virtual void run() = 0;
     };
 
     class BLINK_PLATFORM_EXPORT TaskObserver {
     public:
         virtual ~TaskObserver() { }
         virtual void willProcessTask() = 0;
         virtual void didProcessTask() = 0;
     };
 
     // postTask() and postDelayedTask() take ownership of the passed Task
     // object. It is safe to invoke postTask() and postDelayedTask() from any
     // thread.
     virtual void postTask(Task*) = 0;
     virtual void postDelayedTask(Task*, long long delayMs) = 0;
+    virtual void postCancellableDelayedTask(base::WeakPtrFactory<Task>& task, long long delayMs) { }
 
     virtual bool isCurrentThread() const = 0;
 
     virtual void addTaskObserver(TaskObserver*) { }
     virtual void removeTaskObserver(TaskObserver*) { }
 
     // enterRunLoop() processes tasks posted to this WebThread. This call does not return until some task calls exitRunLoop().
     // WebThread does not support nesting, meaning that once the run loop is entered for a given WebThread it is not valid to
     // call enterRunLoop() again.
     virtual void enterRunLoop() = 0;
 
     // exitRunLoop() runs tasks until there are no tasks available to run, then returns control to the caller of enterRunLoop().
     // Must be called when the WebThread is running.
     virtual void exitRunLoop() = 0;
 
     virtual ~WebThread() { }
 };
 
 } // namespace blink
 
 #endif