Fix unscrollable scrollers after closing a <dialog>.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc.
  * All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
@@ skipping 3373 matching lines @@
 
 void Element::setIsInTopLayer(bool inTopLayer) {
   if (isInTopLayer() == inTopLayer)
     return;
   setElementFlag(IsInTopLayer, inTopLayer);
 
   // We must ensure a reattach occurs so the layoutObject is inserted in the
   // correct sibling order under LayoutView according to its top layer position,
   // or in its usual place if not in the top layer.
   lazyReattachIfAttached();
+
+  // PaintLayerScrollableArea::updateAfterLayout depends on top layer state
+  // via LayoutObject::visibleToHitTesting. See crbug.com/633520 for details.
+  document().layoutView()->setNeedsLayout(

[szager1, 2016/10/17 19:16:30]

Can we condition this on (layoutObject() && layoutObject()->hasOverflowClip())?

[esprehn, 2016/10/17 19:19:58]

This belongs in Document::removeFromTopLayer

[skobes, 2016/10/17 19:45:30]

We can't - the dialog itself is not a scroller.

[skobes, 2016/10/17 19:45:30]

Done.

+      LayoutInvalidationReason::TopLayerChanged);
 }
 
 void Element::requestPointerLock() {
   if (document().page())
     document().page()->pointerLockController().requestPointerLock(this);
 }
 
 SpellcheckAttributeState Element::spellcheckAttributeState() const {
   const AtomicString& value = fastGetAttribute(spellcheckAttr);
   if (value == nullAtom)
@@ skipping 678 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(Element) {
   if (hasRareData()) {
     visitor->traceWrappers(elementRareData());
   }
   ContainerNode::traceWrappers(visitor);
 }
 
 }  // namespace blink