binding: Changes the association among global-proxy/global/window-instance.

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 cc970e70ecff0d9c37674b30f0c53cc4075e405e..86f7ae5098299f762aa7592a496f247be059e03b 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptWrappable.h
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptWrappable.h
@@ -128,6 +128,14 @@ class CORE_EXPORT ScriptWrappable : public TraceWrapperBase {
     return true;
   }
 
+  // Dissociates the wrapper, if any, from this instance.
+  void unsetWrapperIfAny() {
+    if (containsWrapper()) {
+      m_mainWorldWrapper.Reset();
+      WrapperTypeInfo::wrapperDestroyed();
+    }
+  }
+
   bool isEqualTo(const v8::Local<v8::Object>& other) const {
     return m_mainWorldWrapper == other;
   }