Update AbstractWorker, Worker and SharedWorker to match the spec

Source/core/workers/AbstractWorker.cpp

Index: Source/core/workers/AbstractWorker.cpp
diff --git a/Source/core/workers/AbstractWorker.cpp b/Source/core/workers/AbstractWorker.cpp
index 3ca3320407506602751106dd2670432fbfdee794..f173ea55173be98af0066b46e6af7c59c71ea5e5 100644
--- a/Source/core/workers/AbstractWorker.cpp
+++ b/Source/core/workers/AbstractWorker.cpp
@@ -40,21 +40,14 @@
 
 namespace WebCore {
 
-AbstractWorker::AbstractWorker(ScriptExecutionContext* context)
-    : ActiveDOMObject(context)
+AbstractWorker::AbstractWorker()
 {
-    ScriptWrappable::init(this);
 }
 
 AbstractWorker::~AbstractWorker()
 {
 }
 
-void AbstractWorker::contextDestroyed()
-{
-    ActiveDOMObject::contextDestroyed(); 
-}
-
 KURL AbstractWorker::resolveURL(const String& url, ExceptionCode& ec)
 {
     if (url.isEmpty()) {