Remove ActiveDOMObject::willStop, and introduce WorkerGlobalScope::TerminationObserver.

Source/core/workers/WorkerGlobalScope.h

 /*
  * Copyright (C) 2008, 2009 Apple 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
@@ skipping 64 matching lines @@
         const KURL& url() const { return m_url; }
         KURL completeURL(const String&) const;
 
         virtual String userAgent(const KURL&) const OVERRIDE FINAL;
         virtual void disableEval(const String& errorMessage) OVERRIDE FINAL;
 
         WorkerScriptController* script() { return m_script.get(); }
         void clearScript() { m_script.clear(); }
         void clearInspector();
 
-        void willStopActiveDOMObjects();
+        // FIXME: We can remove this interface when we remove openDatabaseSync.
+        class TerminationObserver {
+        public:
+            virtual ~TerminationObserver() { }
+            // The function is called in the main thread.

[haraken, 2014/04/23 09:17:36]

Given that this is not always called from the main thread, shall we drop this
comment?

[tkent, 2014/04/23 09:24:53]

Updated the comment.

+            virtual void wasRequestedToTerminate() = 0;
+        };
+        void registerTerminationObserver(TerminationObserver*);
+        void unregisterTerminationObserver(TerminationObserver*);
+        void wasRequestedToTerminate();
+
         void dispose();
 
         WorkerThread* thread() const { return m_thread; }
 
         virtual void postTask(PassOwnPtr<ExecutionContextTask>) OVERRIDE FINAL; // Executes the task on context's thread asynchronously.
 
         // WorkerGlobalScope
         WorkerGlobalScope* self() { return this; }
         WorkerConsole* console();
         WorkerLocation* location() const;
@@ skipping 65 matching lines @@
         WorkerThread* m_thread;
 
         OwnPtr<WorkerInspectorController> m_workerInspectorController;
         bool m_closing;
 
         OwnPtr<WorkerEventQueue> m_eventQueue;
 
         OwnPtrWillBeMember<WorkerClients> m_workerClients;
 
         double m_timeOrigin;
+        TerminationObserver* m_terminationObserver;
     };
 
 DEFINE_TYPE_CASTS(WorkerGlobalScope, ExecutionContext, context, context->isWorkerGlobalScope(), context.isWorkerGlobalScope());
 
 } // namespace WebCore
 
 #endif // WorkerGlobalScope_h