Remove the concept of a cleanup task

Source/core/workers/WorkerGlobalScope.cpp

Index: Source/core/workers/WorkerGlobalScope.cpp
diff --git a/Source/core/workers/WorkerGlobalScope.cpp b/Source/core/workers/WorkerGlobalScope.cpp
index 48280c3525443f8add1f77792d20956b4acefca2..892f041214dbb73145cf97cb98515f49e2d161e6 100644
--- a/Source/core/workers/WorkerGlobalScope.cpp
+++ b/Source/core/workers/WorkerGlobalScope.cpp
@@ -68,23 +68,6 @@
 
 namespace blink {
 
-class CloseWorkerGlobalScopeTask : public ExecutionContextTask {
-public:
-    static PassOwnPtr<CloseWorkerGlobalScopeTask> create()
-    {
-        return adoptPtr(new CloseWorkerGlobalScopeTask);
-    }
-
-    virtual void performTask(ExecutionContext *context)
-    {
-        WorkerGlobalScope* workerGlobalScope = toWorkerGlobalScope(context);
-        // Notify parent that this context is closed. Parent is responsible for calling WorkerThread::stop().
-        workerGlobalScope->thread()->workerReportingProxy().workerGlobalScopeClosed();
-    }
-
-    virtual bool isCleanupTask() const { return true; }
-};
-
 WorkerGlobalScope::WorkerGlobalScope(const KURL& url, const String& userAgent, WorkerThread* thread, double timeOrigin, const SecurityOrigin* starterOrigin, PassOwnPtrWillBeRawPtr<WorkerClients> workerClients)
     : m_url(url)
     , m_userAgent(userAgent)
@@ -176,14 +159,8 @@ WorkerLocation* WorkerGlobalScope::location() const
 
 void WorkerGlobalScope::close()

[haraken, 2015/05/09 15:54:36]

I'm just curious if we can add ASSERT(!m_closing) here. Can the close() be
called more than once?

[Sami, 2015/05/11 10:35:32]

Correct me if I'm wrong but I think a worker script can still call close twice
in the same task without yielding in the middle:

  self.close();
  self.close();

For that reason I don't think we can assert here.

 {
-    if (m_closing)
-        return;
-
-    // Let current script run to completion but prevent future script evaluations.
-    // After m_closing is set, all the tasks in the queue continue to be fetched but only
-    // tasks with isCleanupTask()==true will be executed.
+    // Let current script run to completion, but tell the worker thread to shut down after the script exits.

[haraken, 2015/05/09 15:54:36]

This comment looks out-dated. We no longer tell the worker thread to shut down
here.

[Sami, 2015/05/11 10:35:32]

Right, I've now tried to make it a little more accurate. Setting m_closing =
true will make trigger the worker micro task runner to cleanup the thread after
the current task.

     m_closing = true;
-    postTask(FROM_HERE, CloseWorkerGlobalScopeTask::create());
 }
 
 WorkerConsole* WorkerGlobalScope::console()
@@ -216,6 +193,11 @@ void WorkerGlobalScope::clearInspector()
 void WorkerGlobalScope::dispose()
 {
     ASSERT(thread()->isCurrentThread());
+    stopActiveDOMObjects();
+
+    // Event listeners would keep DOMWrapperWorld objects alive for too long. Also, they have references to JS objects,
+    // which become dangling once Heap is destroyed.
+    removeAllEventListeners();
 
     clearScript();
     clearInspector();