Fix stale focusedElement in unloaded document.

third_party/WebKit/Source/core/dom/Element.cpp

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index 8e073759aa47850e3b1d3b95e5e5afa1f02ab70e..4b146314627f4c71e8e39040cffaf7eb002c7094 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -2644,6 +2644,11 @@ void Element::focus(const FocusParams& params) {
   if (!document().isActive())
     return;
 
+  if (isFrameOwnerElement() &&
+      toHTMLFrameOwnerElement(this)->contentDocument() &&
+      toHTMLFrameOwnerElement(this)->contentDocument()->unloadStarted())
+    return;
+
   document().updateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
   if (!isFocusable())
     return;