Revert of Make WebTraceLocation be an alias of tracked_objects::Location

third_party/WebKit/public/platform/WebThread.h

 /*
  * Copyright (C) 2011 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 13 matching lines @@
  */
 #ifndef WebThread_h
 #define WebThread_h
 
 #include "WebCommon.h"
 #include <stdint.h>
 
 namespace blink {
 class WebScheduler;
 class WebTaskRunner;
+class WebTraceLocation;
 
 // Always an integer value.
 typedef uintptr_t PlatformThreadId;
 
 // Provides an interface to an embedder-defined thread implementation.
 //
 // Deleting the thread blocks until all pending, non-delayed tasks have been
 // run.
 class BLINK_PLATFORM_EXPORT WebThread {
 public:
@@ skipping 24 matching lines @@
 
     // Returns the scheduler associated with the thread.
     virtual WebScheduler* scheduler() const = 0;
 
     virtual ~WebThread() { }
 };
 
 } // namespace blink
 
 #endif