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

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

Index: third_party/WebKit/Source/bindings/core/v8/ScriptWrappable.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptWrappable.h b/third_party/WebKit/Source/bindings/core/v8/ScriptWrappable.h
index e6f3e2d08e9777152705f98795855ec6532ed91f..66e7deaf68b67db8dfeb46cd23081e3cd0c060e9 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptWrappable.h
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptWrappable.h
@@ -130,6 +130,14 @@ class CORE_EXPORT ScriptWrappable : public TraceWrapperBase {
     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;
   }