Make WebTaskRunner ThreadSafeRefCounted

third_party/WebKit/Source/core/fetch/FetchContext.h

 /*
  * 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 159 matching lines @@
   virtual void addCSPHeaderIfNecessary(Resource::Type, FetchRequest&);
   virtual void populateRequestData(ResourceRequest&);
 
   virtual MHTMLArchive* archive() const { return nullptr; }
 
   virtual ResourceLoadPriority modifyPriorityForExperiments(
       ResourceLoadPriority priority) {
     return priority;
   }
 
-  virtual WebTaskRunner* loadingTaskRunner() const { return nullptr; }
+  virtual RefPtr<WebTaskRunner> loadingTaskRunner() const { return nullptr; }
 
  protected:
   FetchContext() {}
 };
 
 }  // namespace blink
 
 #endif