Turn WorkerLoaderProxy into a threadsafe, ref-counted object.

Source/core/workers/SharedWorkerThread.h

 /*
  * Copyright (C) 2009 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 21 matching lines @@
 
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/workers/WorkerThread.h"
 
 namespace blink {
 
 class WorkerThreadStartupData;
 
 class SharedWorkerThread : public WorkerThread {
 public:
-    static PassRefPtr<SharedWorkerThread> create(const String& name, WorkerLoaderProxy&, WorkerReportingProxy&, PassOwnPtrWillBeRawPtr<WorkerThreadStartupData>);
+    static PassRefPtr<SharedWorkerThread> create(const String& name, PassRefPtr<WorkerLoaderProxy>, WorkerReportingProxy&, PassOwnPtrWillBeRawPtr<WorkerThreadStartupData>);
     virtual ~SharedWorkerThread();
 
 protected:
     virtual PassRefPtrWillBeRawPtr<WorkerGlobalScope> createWorkerGlobalScope(PassOwnPtrWillBeRawPtr<WorkerThreadStartupData>) override;
 
 private:
-    SharedWorkerThread(const String& name, WorkerLoaderProxy&, WorkerReportingProxy&, PassOwnPtrWillBeRawPtr<WorkerThreadStartupData>);
+    SharedWorkerThread(const String& name, PassRefPtr<WorkerLoaderProxy>, WorkerReportingProxy&, PassOwnPtrWillBeRawPtr<WorkerThreadStartupData>);
 
     String m_name;
 };
 
 } // namespace blink
 
 #endif // SharedWorkerThread_h