WorkerThread: drop unnecessary interfaces to simplify

Source/web/WebEmbeddedWorkerImpl.cpp

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 191 matching lines @@
         // This may delete 'this'.
         m_workerContextClient->workerContextFailedToStart();
         return;
     }
     if (m_pauseAfterDownloadState == IsPausedAfterDownload) {
         // This may delete 'this'.
         m_workerContextClient->workerContextFailedToStart();
         return;
     }
     if (m_workerThread)
-        m_workerThread->stop();
+        m_workerThread->terminate();
     m_workerInspectorProxy->workerThreadTerminated();
 }
 
 void WebEmbeddedWorkerImpl::resumeAfterDownload()
 {
     ASSERT(!m_askedToTerminate);
     bool wasPaused = (m_pauseAfterDownloadState == IsPausedAfterDownload);
     m_pauseAfterDownloadState = DontPauseAfterDownload;
 
     // If we were asked to wait for debugger while updating service worker version then it is good time now.
@@ skipping 206 matching lines @@
     m_mainScriptLoader.clear();
 
     m_workerGlobalScopeProxy = ServiceWorkerGlobalScopeProxy::create(*this, *document, *m_workerContextClient);
     m_loaderProxy = WorkerLoaderProxy::create(this);
     m_workerThread = ServiceWorkerThread::create(m_loaderProxy, *m_workerGlobalScopeProxy);
     m_workerThread->start(startupData.release());
     m_workerInspectorProxy->workerThreadCreated(document, m_workerThread.get(), scriptURL);
 }
 
 } // namespace blink