Fix detached event listener attribute updating.

third_party/WebKit/Source/bindings/core/v8/V8AbstractEventListener.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 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 180 matching lines @@
   EventTarget* target = event->currentTarget();
   v8::Local<v8::Value> value =
       ToV8(target, script_state->GetContext()->Global(), GetIsolate());
   if (value.IsEmpty())
     return v8::Local<v8::Object>();
   return v8::Local<v8::Object>::New(GetIsolate(),
                                     v8::Local<v8::Object>::Cast(value));
 }
 
 bool V8AbstractEventListener::BelongsToTheCurrentWorld(
-    ExecutionContext* execution_context) const {
+    Document* document) const {
   if (!GetIsolate()->GetCurrentContext().IsEmpty() &&
       &World() == &DOMWrapperWorld::Current(GetIsolate()))
     return true;
   // If currently parsing, the parser could be accessing this listener
   // outside of any v8 context; check if it belongs to the main world.
-  if (!GetIsolate()->InContext() && execution_context->IsDocument()) {
-    Document* document = ToDocument(execution_context);
-    if (document->Parser() && document->Parser()->IsParsing())
-      return World().IsMainWorld();
+  if (!GetIsolate()->InContext() && document && document->Parser() &&
+      document->Parser()->IsParsing()) {
+    return World().IsMainWorld();
   }
   return false;
 }
 
 void V8AbstractEventListener::ClearListenerObject() {
   if (!HasExistingListenerObject())
     return;
   listener_.Clear();
   if (worker_global_scope_) {
     worker_global_scope_->DeregisterEventListener(this);
@@ skipping 10 matching lines @@
 DEFINE_TRACE(V8AbstractEventListener) {
   visitor->Trace(worker_global_scope_);
   EventListener::Trace(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS(V8AbstractEventListener) {
   visitor->TraceWrappers(listener_.Cast<v8::Value>());
 }
 
 }  // namespace blink