bindings: Supports reentrance to ScriptWrappable::wrap through V8DOMWrapper::createWrapper.

Source/bindings/core/v8/ScriptWrappable.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 
 #include "bindings/core/v8/DOMDataStore.h"
 #include "bindings/core/v8/V8DOMWrapper.h"
 
@@ skipping 33 matching lines @@
     const WrapperTypeInfo* wrapperTypeInfo = this->wrapperTypeInfo();
 
     // It's possible that no one except for the new wrapper owns this object at
     // this moment, so we have to prevent GC to collect this object until the
     // object gets associated with the wrapper.
     ScriptWrappableProtector protect(this, wrapperTypeInfo);
 
     ASSERT(!DOMDataStore::containsWrapper(this, isolate));
 
     v8::Local<v8::Object> wrapper = V8DOMWrapper::createWrapper(isolate, creationContext, wrapperTypeInfo, this);
+    // V8DOMWrapper::createWrapper may run an arbitrary script and it may result
+    // in creating a new wrapper and associating it with |this|.  If so, the
+    // wrapper already created and associated must be used.
+    v8::Local<v8::Object> associatedWrapper = DOMDataStore::getWrapper(this, isolate);
+    if (UNLIKELY(!associatedWrapper.IsEmpty()))
+        return associatedWrapper;
     if (UNLIKELY(wrapper.IsEmpty()))
         return wrapper;
 
     wrapperTypeInfo->installConditionallyEnabledProperties(wrapper, isolate);
     return associateWithWrapper(isolate, wrapperTypeInfo, wrapper);
 }
 
 v8::Local<v8::Object> ScriptWrappable::associateWithWrapper(v8::Isolate* isolate, const WrapperTypeInfo* wrapperTypeInfo, v8::Local<v8::Object> wrapper)
 {
     return V8DOMWrapper::associateObjectWithWrapper(isolate, this, wrapperTypeInfo, wrapper);
 }
 
 } // namespace blink