Improve window.closed fidelity.

Source/core/frame/DOMWindow.cpp

Index: Source/core/frame/DOMWindow.cpp
diff --git a/Source/core/frame/DOMWindow.cpp b/Source/core/frame/DOMWindow.cpp
index 67cd0a2ec76b2e01bbe7cbe5f225357dcf226079..be23dce70fd6b9af82203428a4b079d112b357da 100644
--- a/Source/core/frame/DOMWindow.cpp
+++ b/Source/core/frame/DOMWindow.cpp
@@ -23,6 +23,11 @@
 
 namespace blink {
 
+DOMWindow::DOMWindow()
+    : m_windowIsClosing(false)
+{
+}
+
 DOMWindow::~DOMWindow()
 {
 }
@@ -36,7 +41,7 @@ Location* DOMWindow::location() const
 
 bool DOMWindow::closed() const
 {
-    return !frame() || !frame()->host();
+    return m_windowIsClosing || !frame() || !frame()->host();

[haraken, 2015/04/05 15:06:36]

Do we still need the '!frame() || !frame()->host()' part?

[sof, 2015/04/05 15:09:42]

Yes, windows.close() is just the programmatic way to discard a browsing context.
(closed == true when that context is discarded.)

 }
 
 unsigned DOMWindow::length() const