Extract a DOMWindow interface from LocalDOMWindow and use it in the idl.

Source/core/page/DOMWindowPagePopup.cpp

 /*
  * Copyright (C) 2012 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
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@@ skipping 31 matching lines @@
     ASSERT(popupClient);
 }
 
 DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(DOMWindowPagePopup);
 
 const char* DOMWindowPagePopup::supplementName()
 {
     return "DOMWindowPagePopup";
 }
 
-PagePopupController* DOMWindowPagePopup::pagePopupController(LocalDOMWindow& window)
+PagePopupController* DOMWindowPagePopup::pagePopupController(DOMWindow& window)

[haraken, 2014/11/08 09:17:25]

What's the point of changing LocalDOMWindow to DOMWindow, while we assume that
the window is a LocalDOMWindow below?

[dcheng, 2014/11/08 23:59:56]

This is required by the way the bindings code currently generates code for
partial Window interfaces. The generated code wants to get the object associated
object with Window. But since I changed Window's ImplementedAs to DOMWindow,
bindings code passes around DOMWindow internally now, so it passes a DOMWindow
to these functions now (for example, pagePopupControllerAttributeGetter in the
generated V8Window.cpp).

There are two potential solutions:
1) Take the approach this patch does. Since these attributes should not be
accessible cross-origin, we should only ever have to handle a LocalDOMWindow
here. So just unconditionally cast to LocalDOMWindow.
2) Teach bindings code that it can downcast to LocalDOMWindow before calling
these methods. It could only use this heuristic on DOMWindow, and only with the
default security checks. I rejected this because it felt like it was tying
bindings and the implementation too tightly... but they're already pretty
tightly bound as it is.

[haraken, 2014/11/10 08:58:20]

Ah, understood. I'm fine with your approach :)

 {
-    DOMWindowPagePopup* supplement = static_cast<DOMWindowPagePopup*>(from(&window, supplementName()));
+    DOMWindowPagePopup* supplement = static_cast<DOMWindowPagePopup*>(from(&toLocalDOMWindow(window), supplementName()));
     ASSERT(supplement);
     return supplement->m_controller.get();
 }
 
 void DOMWindowPagePopup::install(LocalDOMWindow& window, PagePopupClient* popupClient)
 {
     ASSERT(popupClient);
     provideTo(window, supplementName(), adoptPtrWillBeNoop(new DOMWindowPagePopup(popupClient)));
 }
 
 void DOMWindowPagePopup::uninstall(LocalDOMWindow& window)
 {
     pagePopupController(window)->clearPagePopupClient();
     window.removeSupplement(supplementName());
 }
 
 void DOMWindowPagePopup::trace(Visitor* visitor)
 {
     visitor->trace(m_controller);
     WillBeHeapSupplement<LocalDOMWindow>::trace(visitor);
 }
 
 }