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

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 e69300be4d291c266a3e3a9daa6ea007a085a5d4..b6175d3d134cac3be2ab168f9771736ec816cc20 100644
--- a/Source/core/workers/WorkerGlobalScope.cpp
+++ b/Source/core/workers/WorkerGlobalScope.cpp
@@ -84,6 +84,7 @@ WorkerGlobalScope::WorkerGlobalScope(const KURL& url, const String& userAgent, W
     , m_eventQueue(WorkerEventQueue::create(this))
     , m_workerClients(workerClients)
     , m_timeOrigin(timeOrigin)
+    , m_terminationObserver(0)
 {
     ScriptWrappable::init(this);
     setClient(this);
@@ -184,9 +185,24 @@ void WorkerGlobalScope::clearInspector()
     m_workerInspectorController.clear();
 }
 
-void WorkerGlobalScope::willStopActiveDOMObjects()
+void WorkerGlobalScope::registerTerminationObserver(TerminationObserver* observer)
 {
-    lifecycleNotifier().notifyWillStopActiveDOMObjects();
+    ASSERT(!m_terminationObserver);
+    ASSERT(observer);
+    m_terminationObserver = observer;
+}
+
+void WorkerGlobalScope::unregisterTerminationObserver(TerminationObserver* observer)
+{
+    ASSERT(observer);
+    ASSERT(m_terminationObserver == observer);
+    m_terminationObserver = 0;
+}
+
+void WorkerGlobalScope::wasRequestedToTerminate()
+{
+    if (m_terminationObserver)
+        m_terminationObserver->wasRequestedToTerminate();
 }
 
 void WorkerGlobalScope::dispose()