Add missing opener frame null check.

third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 1411 matching lines @@
         return;
 
     frameConsole()->addMessage(ConsoleMessage::create(JSMessageSource, ErrorMessageLevel, message));
 }
 
 PassRefPtrWillBeRawPtr<DOMWindow> LocalDOMWindow::open(const String& urlString, const AtomicString& frameName, const String& windowFeaturesString,
     LocalDOMWindow* callingWindow, LocalDOMWindow* enteredWindow)
 {
     if (!isCurrentlyDisplayedInFrame())
         return nullptr;
+    if (!callingWindow->frame())
+        return nullptr;
     Document* activeDocument = callingWindow->document();
     if (!activeDocument)
         return nullptr;
     LocalFrame* firstFrame = enteredWindow->frame();
     if (!firstFrame)
         return nullptr;
 
     UseCounter::count(*activeDocument, UseCounter::DOMWindowOpen);
     if (!windowFeaturesString.isEmpty())
         UseCounter::count(*activeDocument, UseCounter::DOMWindowOpenFeatures);
@@ skipping 68 matching lines @@
 {
     // If the LocalDOMWindow still has a frame reference, that frame must point
     // back to this LocalDOMWindow: otherwise, it's easy to get into a situation
     // where script execution leaks between different LocalDOMWindows.
     if (m_frameObserver->frame())
         ASSERT_WITH_SECURITY_IMPLICATION(m_frameObserver->frame()->domWindow() == this);
     return m_frameObserver->frame();
 }
 
 } // namespace blink