messageHandlerInMainThread should return immediately if there is no entered window

third_party/WebKit/Source/bindings/core/v8/V8Binding.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 658 matching lines @@
     return toDOMWindow(context->GetIsolate(), context->Global());
 }
 
 LocalDOMWindow* enteredDOMWindow(v8::Isolate* isolate)
 {
     LocalDOMWindow* window = toLocalDOMWindow(toDOMWindow(isolate->GetEnteredContext()));
     if (!window) {
         // We don't always have an entered DOM window, for example during microtask callbacks from V8
         // (where the entered context may be the DOM-in-JS context). In that case, we fall back
         // to the current context.
+        //
+        // TODO(haraken): It's nasty to return a current window from enteredDOMWindow.
+        // All call sites should be updated so that it works even if it doesn't have
+        // an entered window.
         window = currentDOMWindow(isolate);
         ASSERT(window);
     }
     return window;
 }
 
 LocalDOMWindow* currentDOMWindow(v8::Isolate* isolate)
 {
     return toLocalDOMWindow(toDOMWindow(isolate->GetCurrentContext()));
 }
@@ skipping 221 matching lines @@
 {
     v8::Local<v8::Value> data = info.Data();
     ASSERT(data->IsExternal());
     V8PerContextData* perContextData = V8PerContextData::from(info.Holder()->CreationContext());
     if (!perContextData)
         return;
     v8SetReturnValue(info, perContextData->constructorForType(WrapperTypeInfo::unwrap(data)));
 }
 
 } // namespace blink