Have window.closed return true when frame is closed.

Source/web/WebRemoteFrameImpl.cpp

Index: Source/web/WebRemoteFrameImpl.cpp
diff --git a/Source/web/WebRemoteFrameImpl.cpp b/Source/web/WebRemoteFrameImpl.cpp
index fa8cf649652b77b0bd3b94c031167ffa12049fd9..f0a16a1e03eb91e991d917f266f6695082ddb0cc 100644
--- a/Source/web/WebRemoteFrameImpl.cpp
+++ b/Source/web/WebRemoteFrameImpl.cpp
@@ -130,6 +130,9 @@ WebRemoteFrame* WebRemoteFrameImpl::toWebRemoteFrame()
 
 void WebRemoteFrameImpl::close()
 {
+    if (m_frame)
+        m_frame->setHasBeenClosed();
+
     deref();
 }
 
@@ -835,4 +838,3 @@ WebRemoteFrameImpl* WebRemoteFrameImpl::fromFrame(RemoteFrame& frame)
 }
 
 } // namespace blink
-