[Reland #1] Don't create layout objects for children of display-none iframes.

third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.cpp

 /*
  * Copyright (C) 2006, 2007, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 205 matching lines @@
 }
 
 void HTMLFrameOwnerElement::disposeWidgetSoon(FrameViewBase* frameViewBase) {
   if (s_updateSuspendCount) {
     widgetsPendingDispose().insert(frameViewBase);
     return;
   }
   frameViewBase->dispose();
 }
 
+void HTMLFrameOwnerElement::frameOwnerPropertiesChanged() {
+  // Don't notify about updates if contentFrame() is null, for example when
+  // the subframe hasn't been created yet.
+  if (contentFrame())
+    document().frame()->loader().client()->didChangeFrameOwnerProperties(this);
+}
+
 void HTMLFrameOwnerElement::dispatchLoad() {
   dispatchScopedEvent(Event::create(EventTypeNames::load));
 }
 
 const WebVector<WebFeaturePolicyFeature>&
 HTMLFrameOwnerElement::allowedFeatures() const {
   DEFINE_STATIC_LOCAL(WebVector<WebFeaturePolicyFeature>, features, ());
   return features;
 }
 
 Document* HTMLFrameOwnerElement::getSVGDocument(
     ExceptionState& exceptionState) const {
   Document* doc = contentDocument();
   if (doc && doc->isSVGDocument())
     return doc;
   return nullptr;
 }
 
 void HTMLFrameOwnerElement::setWidget(FrameViewBase* frameViewBase) {
   if (frameViewBase == m_widget)
     return;
 
+  Document* doc = contentDocument();
+  if (doc && doc->frame()) {
+    bool willBeDisplayNone = !frameViewBase;
+    if (isDisplayNone() != willBeDisplayNone) {
+      doc->willChangeFrameOwnerProperties(marginWidth(), marginHeight(),
+                                          scrollingMode(), willBeDisplayNone);
+    }
+  }
+
   if (m_widget) {
     if (m_widget->parent())
       moveWidgetToParentSoon(m_widget.get(), 0);
     m_widget = nullptr;
   }
 
   m_widget = frameViewBase;
+  frameOwnerPropertiesChanged();
 
   LayoutPart* layoutPart = toLayoutPart(layoutObject());
   LayoutPartItem layoutPartItem = LayoutPartItem(layoutPart);
   if (layoutPartItem.isNull())
     return;
 
   if (m_widget) {
     layoutPartItem.updateOnWidgetChange();
 
     DCHECK_EQ(document().view(), layoutPartItem.frameView());
@@ skipping 58 matching lines @@
 }
 
 DEFINE_TRACE(HTMLFrameOwnerElement) {
   visitor->trace(m_contentFrame);
   visitor->trace(m_widget);
   HTMLElement::trace(visitor);
   FrameOwner::trace(visitor);
 }
 
 }  // namespace blink