Remove OwnPtr from Blink.

third_party/WebKit/Source/platform/heap/Visitor.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 20 matching lines @@
 #ifndef Visitor_h
 #define Visitor_h
 
 #include "platform/PlatformExport.h"
 #include "platform/heap/GarbageCollected.h"
 #include "wtf/Allocator.h"
 #include "wtf/Assertions.h"
 #include "wtf/Forward.h"
 #include "wtf/HashTraits.h"
 #include "wtf/TypeTraits.h"
+#include <memory>
 
 namespace blink {
 
 template<typename T> class GarbageCollected;
 class HeapObjectHeader;
 class InlinedGlobalMarkingVisitor;
 template<typename T> class TraceTrait;
 template<typename T> class TraceEagerlyTrait;
 class ThreadState;
 class Visitor;
@@ skipping 203 matching lines @@
         // GCing thread. This is used for GCType=ThreadTerminationGC.
         ThreadLocalMarking,
         // This visitor just marks objects and ignores weak processing.
         // This is used for GCType=TakeSnapshot.
         SnapshotMarking,
         // This visitor is used to trace objects during weak processing.
         // This visitor is allowed to trace only already marked objects.
         WeakProcessing,
     };
 
-    static PassOwnPtr<Visitor> create(ThreadState*, BlinkGC::GCType);
+    static std::unique_ptr<Visitor> create(ThreadState*, BlinkGC::GCType);
 
     virtual ~Visitor();
 
     using VisitorHelper<Visitor>::mark;
 
     // This method marks an object and adds it to the set of objects
     // that should have their trace method called. Since not all
     // objects have vtables we have to have the callback as an
     // explicit argument, but we can use the templated one-argument
     // mark method above to automatically provide the callback
@@ skipping 52 matching lines @@
 private:
     static Visitor* fromHelper(VisitorHelper<Visitor>* helper) { return static_cast<Visitor*>(helper); }
 
     ThreadState* m_state;
     const MarkingMode m_markingMode;
 };
 
 } // namespace blink
 
 #endif // Visitor_h