binding: Changes the association among global-proxy/global/window-instance (2nd attempt).

third_party/WebKit/Source/bindings/core/v8/ScriptWrappable.h

 /*
  * Copyright (C) 2010 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 112 matching lines @@
       return false;
     }
     main_world_wrapper_.Reset(isolate, wrapper);
     wrapper_type_info->ConfigureWrapper(&main_world_wrapper_);
     main_world_wrapper_.SetWeak();
     DCHECK(ContainsWrapper());
     ScriptWrappableVisitor::WriteBarrier(&main_world_wrapper_);
     return true;
   }
 
+  // Dissociates the wrapper, if any, from this instance.
+  void UnsetWrapperIfAny() {
+    if (ContainsWrapper()) {
+      main_world_wrapper_.Reset();
+      WrapperTypeInfo::WrapperDestroyed();
+    }
+  }
+
   bool IsEqualTo(const v8::Local<v8::Object>& other) const {
     return main_world_wrapper_ == other;
   }
 
   // Provides a way to convert Node* to ScriptWrappable* without including
   // "core/dom/Node.h".
   //
   // Example:
   //   void foo(const void*) { ... }       // [1]
   //   void foo(ScriptWrappable*) { ... }  // [2]
@@ skipping 70 matching lines @@
 #define DECLARE_WRAPPERTYPEINFO()                             \
  public:                                                      \
   const WrapperTypeInfo* GetWrapperTypeInfo() const override; \
                                                               \
  private:                                                     \
   typedef void end_of_define_wrappertypeinfo_not_reached_t
 
 }  // namespace blink
 
 #endif  // ScriptWrappable_h