Call LocalDOMWindow::clearDocument when a frame gets detached

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

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 4490 matching lines @@
       view->updateViewportIntersectionsForSubtree(targetState);
   }
 }
 
 void FrameView::updateRenderThrottlingStatusForTesting() {
   m_visibilityObserver->deliverObservationsForTesting();
 }
 
 void FrameView::updateRenderThrottlingStatus(bool hidden,
                                              bool subtreeThrottled) {
+  if (!m_frame->document())
+    return;
+
   TRACE_EVENT0("blink", "FrameView::updateRenderThrottlingStatus");
   DCHECK(!isInPerformLayout());
-  DCHECK(!m_frame->document() || !m_frame->document()->inStyleRecalc());
+  DCHECK(!m_frame->document()->inStyleRecalc());
   bool wasThrottled = canThrottleRendering();
 
   // Note that we disallow throttling of 0x0 frames because some sites use
   // them to drive UI logic.
   m_hiddenForThrottling = hidden && !frameRect().isEmpty();
   m_subtreeThrottled = subtreeThrottled;
 
   bool isThrottled = canThrottleRendering();
   bool becameUnthrottled = wasThrottled && !isThrottled;
 
@@ skipping 43 matching lines @@
     DCHECK(canThrottleRendering() || !parent->canThrottleRendering());
     parent = parent->parentFrameView();
   }
 #endif
 }
 
 // TODO(esprehn): Rename this and the method on Document to
 // recordDeferredLoadReason().
 void FrameView::maybeRecordLoadReason() {
   FrameView* parent = parentFrameView();
-  if (frame().document()->frame()) {
+  if (frame().document() && frame().document()->frame()) {
     if (!parent) {
       HTMLFrameOwnerElement* element = frame().deprecatedLocalOwner();
       if (!element)
         frame().document()->maybeRecordLoadReason(WouldLoadOutOfProcess);
       // Having no layout object means the frame is not drawn.
       else if (!element->layoutObject())
         frame().document()->maybeRecordLoadReason(WouldLoadDisplayNone);
     } else {
       // Assume the main frame has always loaded since we don't track its
       // visibility.
@@ skipping 64 matching lines @@
   DCHECK(m_frame->isMainFrame());
   return m_initialViewportSize.width();
 }
 
 int FrameView::initialViewportHeight() const {
   DCHECK(m_frame->isMainFrame());
   return m_initialViewportSize.height();
 }
 
 }  // namespace blink